GIFT  OF 


HEALTHFUL  LIVING 


p. 


THE  MACMILLAN  COMPANY 

NEW  YORK    •    BOSTON   •    CHICAGO   •    DALLAS 
ATLANTA  •    SAN   FRANCISCO 

MACMILLAN  &  CO.,  LIMITED 

LONDON   •    BOMBAY   •    CALCUTTA 
MELBOURNE 

THE  MACMILLAN  CO.  OF  CANADA,  LTD, 
TORONTO 


HEALTHFUL   LIVING 

BASED  ON  THE  ESSENTIALS  OF  PHYSIOLOGY 
FOR  HIGH  SCHOOL  PUPILS 


BY 
JESSE   FEIRING    WILLIAMS,  A.B.,  M.D. 

ASSOCIATE    PROFESSOR    OF    PHYSICAL    EDUCATION,    TEACHERS    COLLEGE 

COLUMBIA    UNIVERSITY 
FORMERLY    PROFESSOR    OF    HYGIENE    AND    PHYSICAL    EDUCATION 

UNIVERSITY    OF    CINCINNATI 
LIEUTENANT   IN    MEDICAL    CORPS,    UNITED    STATES   ARMY 


Illustrations  by  B.  F.  Williamson 


Nefo  gorfc      v 

THE   MACMILLAN   COMPANY 
1921 

All  righto  reserved 


QP.3& 


COPTBIOHT,   1919, 

'./i  b^THE  MACMILLAN  COMPANY. 
S^  vi^nd  eicctrotyped.     Published  July,  1919. 


INTRODUCTION 

IN  writing  this  book,  I  have  been  guided  by  two  con- 
siderations :  first,  to  present  the  essentials  of  physiology 
for  the  high  school  pupil  in  a  form  that  would  provide 
motives  and  material  that  would  enable  him  to  interpret 
intelligently  conditions  underlying  the  problem  of  effective 
living,  and  second,  to  limit  the  technical  discussion  without 
making  the  subject  matter  worthless  as  a  scientific  text, 
incapable  of  providing  the  background  necessary  to  secure 
the  first  consideration. 

As  regards  the  limiting  of  material,  it  is  evident  that  the 
selection  of  what  to  give  and  what  to  omit  is  a  matter  of 
judgment  on  the  part  of  the  author.  If  that  judgment  is 
to  be  approved  by  the  educational  world  interested,  then 
the  anatomy  should  have  a  definite  relation  to  the  physiology, 
and  the  physiology,  although  it  may  give  incidentally  a 
scientific  basis  for  more  advanced  study,  should  be  deter- 
mined by  the  larger  question  of  usefulness  in  understanding 
essential  life  processes. 

The  material  and  the  method  of  presentation  have  been 
tried  out  for  several  years  with  many  students  and  there  is 
reason  for  feeling  that  a  proper  and  satisfactory  selection  of 
physiologic  facts  and  principles  has  been  made. 

It  is  interesting  to  note  that  at  one  time  physiology  in  the 
schools  was  merely  the  teaching  of  anatomy.  "How  many 
bones  in  the  skeleton?"  was  a  typical  question.  As  the 
texts  improved  and  the  method  changed,  function  was 
emphasized,  and  in  most  texts  to-day,  the  presentation  of 

v 

450954 


vi  Introduction 

function  is  the  goal  of  endeavor.  It  should  be  remembered, 
however,  that  knowledge  of  the  structure  and  function  of  the 
body  is  of  value  in  proportion  as  it  helps  the  boy  or  girl  to 
live  a  finer  and  more  vigorous  life,  or  as  it  lays  the  foundation 
for  further  study  in  this  field.  As  regards  these  values,  it 
may  serve  effectively  to  teach  not  only  hygiene,  but  also 
social  science  and  ethics. 

The  study  of  physiology  should  arouse  interest  in  health 
in  the  student  and  provide  guidance  for  intelligent  care  of 
the  body.  One  effect  of  civilization  on  the  race  is  that 
health  is  increasingly  harder  to  maintain.  The  gradual 
but  pronounced  change  in  the  character  of  our  food,  the 
increasing  emphasis  laid  upon  studies,  the  prevalence  of  bad 
housing  conditions,  the  increase  in  sedentary  occupations, 
and  the  enforced  use  of  the  transportation  facilities  are  a 
few  of  the  forces  arrayed  against  the  maintenance  of  health. 
The  school  does  not  stand  alone  and  unrelated  to  these 
problems,  and  physiology  to  be  of  most  service  must  help 
to  educate  the  child  in  the  nature  of  the  human  body  and  the 
dangers  that  confront  its  growth,  development,  and  efficiency. 

With  this  object  in  mind,  distinct  emphasis  is  given  the 
application  of  the  physiological  fact  to  the  life  of  the  reader. 
Therefore,  relatively  little  space  is  devoted  to, the  study  of 
the  mechanism  of  the  eye  and  ear ;  but  the  physiology  of 
exercise  is  stated  prominently,  both  in  text  and  in  illustra- 
tion. The  wisdom  of  such  a  course  will  be  clear  to  every 
one  whether  he  judges  by  the  standards  of  "pure  science" 
or  by  those  of  "applied  science." 

Spirited  questions,  which  should  suggest  many  others  of 
similar  character,  are  placed  at  the  end  of  chapters.  There 
are  numerous  laboratory  experiments  ;  most  of  these  require 
only  the  simplest  apparatus  or  none  at  all.  The  text  is  not 
impaired  if  the  experiments  are  not  performed,  but  its  value 
is  increased  by  the  demonstration  of  both  structure  and  func- 
tion. At  the  close  of  each  chapter  is  a  glossary  of  technical 


Introduction  vii 

terms  used  in  that  chapter.  There  is  no  thought  of  doing 
away  with  the  need  for  consultation  or  reference  books ; 
they  are  always  necessary,  and  the  brief  glossary  should 
stimulate  to  greater  use  of  dictionary  and  encyclopedia. 

To  acknowledge  the  service  of  those  who  have  contributed 
in  the  preparation  of  this  book,  gives  me  especial  pleasure. 
The  organization  is  based  partly  on  the  plan  of  Coleman's 
Elements  of  Physiology.  All  rights  in  that  work  have  been 
purchased  by  the  publishers  and  this  new  book  is  offered  to 
the  school  public  without  apology  for  similarities  or  identities, 
which  are  many.  The  task  was  to  remodel  a  structure  that 
had  been  very  valuable  but  was  now  in  need  of  repairs. 
The  repairs  have  been  made  but  it  would  ill  become  me  to 
deny  the  old  in  my  enthusiasm  for  the  new. 

To  Miss  Marguerite  Smith  for  the  picture  of  girls'  athletics, 
to  Miss  Mary  Gross  for  excellent  illustrations  of  posture, 
to  Dr.  Frank  S.  Matthews  for  the  splendid  pictures  of  adenoid 
deformity,  to  Dr.  Thomas  D.  Wood  for  numerous  health 
essentials  which  he  has  proposed,  I  desire  to  express  my 
thanks. 

Students,  instructors  and  friends  who  have  gone  over  this 
subject  with  me  share  with  me  whatever  merit  the  book 
may  have,  but  I  desire  especially  to  acknowledge  the  in- 
spiration and  help  of  Professor  Henry  Carr  Pearson,  prin- 
cipal of  the  Horace  Mann  School. 

The  criticism  and  suggestions  of  Professor  Edward  Law- 
rence Hall-Quest,  of  the  University  of  Cincinnati,  have  been 
valuable  indeed.  Professor  Hall-Quest  has  read  the  entire 
manuscript,  correcting  mistakes  and  revising  statements. 
Numerous  conferences  with  Professor  William  Paxton 
Burris,  Dean  of  Teachers  College  of  the  University  of  Cin- 
cinnati have  resulted  in  substantial  aid  in  preparing  the 
manuscript. 

Credit  should  be  given  to  the  Harvard  Apparatus  Co., 
The  Metropolitan  Life  Insurance  Co.,  The  American  Posture 


viii  Introduction 

League,  and  The  Scientific  Temperance  Federation  for 
the  privilege  of  reproducing  illustrations  that  have  appeared 
in  other  publications. 

With  such  an  indebtedness,  I  hesitate  to  call  the  book  my 
own.     However,  I  am  glad  to  owe  something  to  all  of  these. 

J.  F.  W. 


CONTENTS 

PART  I 
HOW  THE   BODY  IS  CONSTRUCTED       * 

PTER  PAGE 

I.  THE  CELLS  OF  THE  BODY 1-11 

The  cell,  the  unit  of  structure.  The  origin  of  cells. 
The  properties  of  cells.  Tissues  formed  from  cell  groups. 
Organs  formed  from  tissues.  Similarity  between  living 
organisms  and  social  groups.  Similarity  between  the 
human  body  and  a  city. 

II.  TISSUES 12-37 

Kinds  of  tissues.  Epithelial  tissues.  Indications  of 
good  health. 

III.  TISSUES  (continued) 38-59 

Connective  tissues.  Muscular  tissues.  Nervous 
tissues.  Building  good  tissues. 

IV.  ORGANS  FORMED  FROM  TISSUES          ....     60-71 

The  different  systems  in  the  body.  Organs  of  the 
muscular  system.  Organs  of  the  skeletal  system. 
Organs  of  the  digestive  system.  Organs  of  the  respira- 
tory system.  Organs  of  the  circulatory  system.  Organs 
of  the  nervous  system.  Organs  of  the  excretory  sys- 
tem. Organs  of  the  reproductive  system. 

PART  II 
HOW  THE  BODY  IS  MOVED 

V.  THE  SKELETON  FRAMEWORK  OF  THE  BODY      ".         .     72-94 

The  use  of  the  skeleton.  Parts  of  the  skeleton.  The 
structure  of  a  long  bone.  The  composition  of  bone. 
Joints. 

ix 


x  Contents 

CHAPTER  PAGE 

VI.  HYGIENE  OF  THE  SKELETON     .         .  .      95-108 

The  nourishment  of  bones.  Broken  bones.  Dis- 
locations and  sprains.  Weak  feet.  Deformities  of  the 
spinal  column.  Posture.  Essential  facts  in  the  growth 
and  development  of  bones. 

VII.  THE  MUSCLES 'AS  THE  MOTOR  MACHINERY  OF  THE 

BODY          .         .  r    V' 109-121 

What  the  muscles  do.  Muscles  and  nerves.  Kinds 
of  muscles.  Voluntary  and  involuntary  muscles  com- 
pared. The  attachment  of  muscles.  How  muscles  and 
bones  cooperate.  Names  and  positions  of  muscles. 

VIII.  THE  MUSCLES  IN  ACTION  AND  THE  HYGIENE  OF 

EXERCISE 122-145 

The  neuro-muscular  mechanism.  Muscular  energy. 
Muscular  tone.  Muscular  activity  and  fatigue.  The 
effects  of  stimulants  and  narcotics  on  muscular  action. 
The  effect  of  exercise  on  growth.  The  relation  of  exer- 
cise to  health.  Forms  of  exercise.  Over-development 
.of  the  muscles. 

PART  III 
HOW  THE   BODY  IS   NOURISHED 

IX.  FOOD  AND  ITS  ELEMENTS 146-157 

Nutritive  and  non-nutritive  elements  in  food.  Com- 
position of  foods.  Sources  of  food  elements.  Uses  of 
food  in  the  body.  Proportion  of  food  elements  in  a 
normal  diet.  Calculation  of  food  values.  The  diet  of 
different  peoples.  The  body's  method  of  regulating  the 
food  supply.  The  work  of  enzymes  in  digestion. 

X.  THE  DIGESTION  OF  FOOD 158-188 

The  structure  and  functions  of  the  alimentary  canal. 
The  liver.  Diagram  of  digestive  mechanism.  The 
waste  products  from  food  elements. 

XI.  THE  HYGIENE  OF  DIGESTION  .        .  tt.  .      .  .     189-210 

Digestion  and  health.  Digestion  and  environment. 
Hobbies  about  nutrition.  Man's  original  food  re- 


Contents  xi 


sources  and  how  they  have  been  enlarged.  Present  day 
sources  of  food.  Patent  medicines.  Eating  and  drink- 
ing at  meals.  General  rules  modified  by  individual 
needs.  Cooking.  The  fireless  cooker.  Times  for  eating. 

XII.  THE  CIRCULATION  OF  THE  BLOOD    ....     211-234 

How  the  circulation  of  blood  serves  the  body.  The 
nature  of  circulation.  The  composition  of  the  blood. 
The  heart  as  a  pump.  The  blood  vessels  as  tubes. 
Blood  pressure.  The  heart  rate. 

XIII.  THE  CIRCULATION  OF  THE  BLOOD  (continued)        .     235-255 

How  the  heart  is  aided  in  its  work.  The  lymphatic 
circulation.  Hygiene  of  the  circulation. 

XIV.  THE  RESPIRATION 256-285 

Why  breathing  organs  are  needed.  The  respiratory 
organs.  The  breathing  process.  The  air  we  breathe. 
The  hygiene  of  respiration. 


PART  IV 
HOW  THE   BODY   IS   CONTROLLED 

XV.  THE  NERVOUS  SYSTEM 286-315 

The  functions  of  the  nervous  system.  The  nerve  cell 
the  unit  of  the  nervous  system.  Nerve  action.  Sensations. 
Injury  to  nerves.  General  arrangement  of  the  nervous 
system. 

XVI.  HYGIENE  OF  THE  NERVOUS  SYSTEM         .         .        .     316-331 

Connection  between  body  and  mind.  The  effect  of 
activity  of  the  nervous  system.  The  effect  of  sleep.  The 
effect  of  fatigue.  The  effect  of  alcohol.  Improper  func- 
tioning of  the  nervous  system.  Ten  Golden  Rules  of 
Health. 

XVII.  SENSATIONS  AND  THE  SPECIAL  SENSES    .         .         .     332-356 

Classification  of  the  senses.  The  sense  of  taste.  The 
sense  of  smell.  The  sense  of  sight.  The  sense  of  hearing. 
The  sense  of  touch.  The  muscular  sense.  General 
sensations  of  the  body. 


xii  Contents 

CHAPTER  PAGE 

XVIII.  SOME  SPECIAL  REGULATIVE  PROCESSES  .        .        .    357-367 

The  regulation  of  the  temperature  of  the  body.  The 
regulation  of  body  activity  and  growth.  The  control  of 
the  voice. 

PART  V 
HOW  THE  BODY  IS  INJURED 

XIX.  BACTERIA  AND  DISEASE  ......     368-399 

Injury  to  the  body  by  forces  in  its  environment. 
Microscopic  forms  of  life.  The  effects  of  bacterial 
growth  in  the  body.  The  germ  theory  of  disease. 
Anti-toxins  and  immunity.  Injury  of  the  body  -by 
poisons  in  food.  Injury  of  the  body  by  physical  agents. 
Injury  of  the  body  by  chemical  agents.  Diseases  caused 
by  mosquitoes.  Tuberculosis.  Prevention  of  commu- 
nicable diseases.  Table  of  ways  and  means  of  com- 
munication of  the  important  infections  of  man.  How 
bacteria  are  destroyed  within  the  body.  How  bacteria 
are  destroyed  outside  the  body.  A  curious  theory  of 
disease.  Health  rules  for  school  children. 

XX.  THE  EFFECT  OF  ALCOHOL  AND  TOBACCO         .        .     400-416 

The  body  as  a  storehouse  of  energy.  The  meaning  of 
fatigue.  The  effect  of  stimulants  on  energy  and  nerves. 
Alcohol.  Tobacco. 

APPENDIX.    FIRST  AID  IN  EMERGENCIES  417-426 


HEALTHFUL  LIVING 


HEALTHFUL  LIVING 

CHAPTER   I 
THE    CELLS    OF   THE   BODY 

I.    The  Cell,  the  Unit  of  Structure. 
Protoplasm 
Nucleus 

One-celled  animals 
II.    The  Origin  of  Cells. 

III.  The  Properties  of  Cells. 

IV.  Tissues  Formed  from  Cell  Groups. 
V.    Organs  Formed  from  Tissues. 

VI.    Similarity  between  Living  Organisms  and  Social  Groups. 
One-celled  animals  and  primitive  society 
The  developed  body  and  modern  society 
VII.   Similarity  between  the  Human  Body  and  a  City. 


The  cell,  the  unit  of  structure.  —  A  brick  wall  is  con- 
structed from  bricks.  Assembled  in  a  certain  order,  they 
are  the  parts  which  compose  the  wall.  It  makes  no  dif- 
ference whether  the  brick  is  round,  square,  or  irregular, 
whether  it  is  painted  red,  green,  or  blue ;  it  remains,  in  all 
cases,  the  unit  out  of  which  the  wall  is  built.  Consequently 
we  speak  of  the  brick  as  being  the  unit  of  structure  of  the 
wall  (Fig.  1,  A).  In  similar  fashion,  all  forms  of  life  are 
composed  of  cells.  Plants  and  animals  are  both  constructed 
from  cells.  They  may  vary  in  shape,  size,  color,  and  ac- 
tivity, but,  nevertheless,  they  are  to  be  considered  as  the 
units  of  structure.  These  units  are  so  small  that  they  can 
be  seen  only  by  means  of  the  microscope,  but  when  we  look 


-Healthful  Living 


FIG.  1.  —  A,  brick  wall ;  B,  segment  of  orange  ; 
C,  cells  from  stomach.  The  cell  is  the  unit  of  struc- 
ture. Relative  size  is  not  shown.  The  cells  in  C 
are  much  smaller  than  the  cells  in  B. 


at  them  through  this  instrument,  we  notice  that  they  are 
as  definite  in  shape  as  the  bricks  in  a  brick  wall  (Fig.  1,  C). 

The     cells     of 

3  0123^^  •  ^j^M^^        Plant  and  animal 

are  not  hard  and 
solid  as  bricks 
are.  On  the  con- 
trary, they  are 
soft  and  liquid. 
It  is  quite  com- 
mon to  think  of 
an  orange  as  a 
solid  substance, 
and  yet  the 
orange  is  composed  of  cells  which  are  filled  with  a  liquid, 
the  juice.  If  we  break  open  the  segment  of  an  orange, 
we  can  see  the  cells  with  the  unaided  eye,  and  if  we  prick 
one  of  them  the  juice  will  run  out  (Fig.  1,  B). 

Protoplasm*  —  The  liquid  substance  of  which  the  body 
cell  is  made  is  called  protoplasm,  and  this  name  is  applied 
to  the  cell  substance  of  both 
animals  and  plants.  Workers 
with  the  microscope,  many 
years  ago,  found  that  plant 
and  animal  tissues  are  com- 
posed of  cells,  and  that  the 
liquid  in  the  cells  is  of  more 
importance  than  the  walls  F[G  2  _Diagram  of  .  coll 

Which   the   protoplasm    builds    Showing    that    protoplasm    has    an 
around  itself.  intricate  structure;    in  this  case  it 

appears  somewhat  like  honeycomb. 

We  should   not  think  be- 
cause we  use  the  same  name,  protoplasm,  for  the  substance 
forming  the  cellular  material  of  both  plants  and  animals, 

*  Words  marked  with  a  star  *  are  defined  in  the  glossary  at  the  end  of  each 
chapter. 


Nuc/eofus 
•Protoplasm 


The  Cells  of  the  Body 


that  its  chemical  composition  is  always  the  same  (Fig.  2). 

It  is  best  to  think  of  it  as  a  substance  that  makes  possible 

the  life  and  activity  of  the  cell  rather  than  as 

a  substance  that  has  definite  and  fixed  chemical 

properties.     Furthermore,  it  is  important  to 

remember  that  the  composition  of  protoplasm 

varies  in  the  same  cell   according  to  many 

factors.     Exercise,    food,   fresh   air,   alcohol, 

and  disease  cause  changes  in  the  protoplasm. 

Some  of   these  changes  are  favorable.     Can 

you  name,  from  the  above,  the  factors  which 

cause   unfavorable   changes?     Physiology  is 

the  study  of  the  way  this  protoplasm  acts  in 

the  cells  of  the  body. 

Nucleus.  —  A  living  cell  has  two  essential 
parts.  One  is  a  small  mass  or  globule*  of 
protoplasm,  and  the  other  is  a  small  body 
within  the  mass  of  protoplasm,  called  the 
nucleus  *  (Fig.  2) .  There  are  two  other  parts 
of  less  importance.  Within  the  nucleus  there 
may  be  a  small  body,  called  the  nudeolus* 
and  usually  the  protoplasm  has  a  membrane 
surrounding  it,  called  the  wall.  The  nucleus 
is  the  vital  part  of  the  cell.  If  a  cell  is 
divided,  that  portion  containing  the  nucleus 
alone  survives.  After  they  lose  their  nucleus, 
the  red  cells  of  the  blood  live  only  a  few  days. 

One-celled  animals.  —  The  cells  of  the  body, 
owing  to  the  fact  that  they  have  a  wall,  soft  food    (as    seen 
contents,  and  a  nucleus,  resemble  minute  one-  UQ^    ^f  h^e 
celled  animals  sometimes  found  in  stagnant  microscope), 
water.     Figure  3  shows  the  appearance  under 
the  microscope  of  the  amoeba,  one  of  these  small  animals. 
The  amoeba  seems  to  be  hardly  more  than  a  minute  drop  of 
jelly,  yet  it  lives  and  does  in  a  simple  way  many  of  the  things 


Healthful  Living 


that  the  human  body  can  do.  It  moves  by  pushing  out  a 
part  of  its  body ;  it  takes  in  food  by  rolling  a  process  of  its 
body  around  the  food  to  be  eaten ;  and  after  digesting  the 
part  it  wants,  it  discards  the  indigestible  portion  of  the  food. 
If  the  amoeba  is  struck  or  jarred,  it  reacts  by  moving  its  body. 
It  absorbs  oxygen  *  from  the  air  and  it  gives  off  carbon  dioxide.* 
When  it  attains  a  certain  .size,  it  divides  into  two  parts.  It 
does  not  divide,  however,  and  produce  new  individuals 
until  it  has  reached  its  full  growth.* 
The  origin  of  cells.  —  For  many 
years  it  was  believed  that  life  origi- 
nated spontaneously.  This  viev 
is  called  the  theory  of  spontane 
ous  generation.  We  know  now, 
however,  that  all  cells  are  derived 
from  cells  (Fig.  4)  and  that  the  vast 
number  of  different  cells  which  com- 
pose a  living  body  are  all  derived 
from  two  single  cells,  the  ovum* 
(Fig.  5)  and  the  spermatozoon* 
The  health  and  strength  of  these  two 
cells  are  dependent  upon  the  health, 
strength,  and  vigor  of  the  whole 
body.  In  this  respect,  the  strength 
and  vigor  of  the  race  are  dependent 
upon  the  strength  and  vigor  of  each 
member  of  the  race.  This  is  an  im- 
portant responsibility  because  each 
person,  by  being  strong  and  vigorous, 
makes  it  possible  for  coming  genera- 
tions to  have  health  and  strength. 
In  this  way,  health  is  a  duty  that 
no  one  may  neglect. 
The  properties  of  cells.  —  If  we  say  that  a  stone  is  hard, 
that  it  sinks  when  thrown  into  the  water,  that  it  will  break 


FIG.  4.  —  A  cell  under- 
going division.  A,  cell  be- 
fore division ;  B,  thread-like 
formation  of  the  vital  parts 
of  the  nucleus ;  C,  equal  di- 
vision of  the  nuclear  thread  ; 
D,  separation  of  the  nuclear 
structure  for  the  new  cells 
and  commencing  constric- 
tion of  cell  body ;  E,  nuclei 
beginning  return  to  resting 
states ;  F,  complete  division 
of  cell  body  into  daughter 
cells  whose  nuclei  have  re- 
turned to  the  resting  states. 


The  Cells  of  the  Body  5 

when  hit  with  sufficient  force,  we  are  speaking  of  the  proper- 
ties *  that  belong  to  the  stone.     Cells  also  have  properties  — 


FIG.  5.  —  Different  stages  in  the  development  of  the  frog's  egg  (-4)  to 
form  the  body  of  the  frog.  In  D  the  egg  (ovum)  has  divided  many  times, 
and  presently  these  cells  will  begin  to  change  into  bone,  nerve,  and  muscle 
cells,  and  other  types  of  body  cells. 

the  characteristics  which  distinguish  them  from  other  struc- 
tures. 

In  the  first  stages  of  the  formation  of  the  body,  the  cells 
which  later  on  develop  into  muscle  cells,  or  nerve  cells,  or 
skin  cells,  look  very  much  alike  and  have  identical  properties. 
They  can  divide  and  reproduce  themselves  (the  property  of 
reproduction*) ;  they  can  take  up  food  and  build  it  into  tissue  * 
and  remove  the  waste  (the  property  of  metabolism  *) ;  they  can 
receive  an  impulse  and  conduct  it  to  all  parts  of  the  cell  (the 
property  of  irritability  *  and  conductivity  *) ;  they  can  respond 
to  a  stimulus  and  contract  the  cell  body  (the  property  of 
contractility  *) . 

They  also  change  in  their  properties.  Certain  cells  be- 
come unable  to  contract,  but  are  very  proficient  in  sending 
nerve  impulses ;  others  cannot  secrete  digestive  juices,  but 
they  are  able  to  reproduce  the  individual.  We  say,  there- 
fore, that  the  sex  cells  develop  the  property  of  reproduction, 
the  nerve  cells  the  properties  of  irritability  and  conductivity  ; 
the  digestive  and  excretory  cells  develop  the  property  of  me- 
tabolism, and  the  muscle  cells  the  property  of  contractility. 

Tissues  formed  from  cell  groups.  —  Cells  of  one  kind 
group  .themselves  together  to  perform  a  particular  function 
and  are  called  a  tissue.  We  speak  of  muscle  tissue,  and  we 


6  Healthful  Living 

understand  that  there  is  this  grouping  of  many  muscle  cells 
for  the  purpose  of  contraction.  Therefore,  a  group  of  cells 
of  a  particular  kind  to  perform  a  particular  function  is  known 
as  a  tissue  (Figs.  6,  7,  8). 

Organs  formed  from  tissues.  —  Tissues  combine  to  per- 
form more  effectively  a  highly  complex  act.  The  resulting 
structure  is  an  organ.  Tissues  grouped  in  a  definite  way  to 
cooperate  their  tissue  functions  in  some  special  task  are 
known  as  an  organ.  The  stomach,  for  example,  is  an  organ 
composed  of  muscle,  nerve,  and  connective  tissues,  and  each 
tissue  cooperates  in  the  digestion  of  food  in  the  stomach.  The 
muscle  contracts  the  stomach  and  moves  the  food  at  the 
proper  time  into  the  intestine;  the  nerve  tissue  tells  the 
muscles  when  to  contract,  and  the  epithelial  cells  when  to 
secrete  digestive  juice ;  and  the  connective  tissue  binds  the 
other  tissues  together  to  produce  the  whole  organ. 

Similarity  between  living  organisms  and  social  groups.  — 
It  has  been  learned  that  the  body  is  composed  of  cells  with 
special  properties  grouped  into  tissues ;  that  the  tissues  are 
arranged  to  form  organs.  An  individual  constructed  to 
carry  on  the  activity  of  life  by  means  of  parts  or  organs 
which  are  separate  and  yet  dependent  upon  each  other  is 
called  an  organism*  Man  is,  therefore,  frequently  referred 
to  as  an  organism.  The  term  is  sometimes  used  with  refer- 
en^ce  to  society.  The  relation  of  the  parts  of  the  body  to  the 
whole  body  and  of  the  individual  man  to  the  organism  of 
society  is  very  important.  We  have  learned  that  there  are 
organisms  composed  of  only  one  cell  and  that  such  organisms 
may  show  all  the  properties  of  living  matter.  As  soon  as 
an  organism  becomes  multicellular,*  an  arrangement  is  nec- 
essary for  groups  of  cells  to  take  up  certain  special  tasks. 
This  arrangement  and  organization  permits  greater  achieve- 
ment in  the  group  because  certain  cells  are  free  to  accomplish 
results  which  would  have  been  impossible  in  an  unicellular  * 
type  of  organism. 


The  Cells  of  the  Body  7 

This  division  of  labor  among  cells  may  be  likened  to  a 
similar  division  of  labor  that  occurs  in  human  society.  A 
city  with  its  million  inhabitants  is  a  superior  social  group 
for  the  performing  of  greater  tasks  than  are  possible  for  the 
people  in  a  pioneer  settlement.  In  this  respect,  the  organism, 
man,  is  superior  to  the  amoeba.  Both  man  and  a  city  are 
superior  as  types  because  they  have  greater  opportunities 
and  can  make  better  use  of  abilities  in  acts  that  enrich  the 
life  of  the  world.  The  city  is  more  complex,  more  alive, 
more  sensitive  than  the  pioneer  settlement,  but  in  order  to 
maintain  this  highly  specialized  state  it  must  be  exceedingly 
watchful  against  disease  *  and  degeneration.*  In  this  same 
way,  man,  a  highly  specialized  organism,  superior  to  the 
unicellular  animals,  needs  to  be  careful  of  the  laws  of  life 
and  health,  the  observance  of  which  makes  such  high  special- 
ization *  possible.  In  each  case  then,  in  animal  life  and  in 
human  society,  specialization  produces  a  superior  life,  but 
it  also  produces  the  need  for  intelligent  care  of  the  basis  of 
life.  The  castle  needs  a  better  foundation  than  the  kennel. 

One-celled  animals  and  primitive  society.  —  The  basis  of 
life  for  the  complex  organism  is  the  same  as  that  for  the 
simple  organism.  The  amoeba  in  its  self-dependence  is  like 
the  savage  living  alone.  Modern  man  with  his  highly  de- 
veloped body  is  like  the  organization  of  a  great  city.  In 
each  case,  however,  the  simple  organism  and  the  complex 
organism  resemble  each  other  by  requiring  food,  air,  and 
water,  by  needing  activity  of  the  proper  kind  and  the  re- 
moval of  body  waste.  In  a  complex  society,  it  is  necessary 
that  all  groups  of  men  do  their  special  tasks  well.  In  a 
similar  fashion,  man  must  look  for  his  strength  and  security 
to  the  proper  functioning  of  all  his  cells,  and  in  no  instance 
may  he  with  impunity  sacrifice  the  removal  of  waste  to  the 
development  of  the  nerve  cell.  All  must  be  cared  for. 

The  developed  body  and  modern  society.  —  The  more  com- 
plex an  organism  becomes  the  greater  is  the  necessity  for 


8  Healthful  Living 

cooperation.  In  human  groups  there  is  this  important  re- 
lation between  men  and  women  and  their  fellow  members  in 
society,  which  illustrates  the  cooperation  required  in  the 
developed  body.  Members  of  the  human  family  are  de- 
pendent upon  each  other.  The  chemist  has  to  rely  upon 
the  integrity  of  the  manufacturer  of  chemical  apparatus ; 
the  farmer  is  dependent  upon  the  chemist  for  a  complete  and 
accurate  analysis  of  his  soil ;  the  child  in  school  is  dependent 
upon  the  teacher  for  guidance  and  instruction ;  and  every 
man  must  rely  upon  other  men  to  do  their  work  honestly 
and  efficiently.  Therefore,  just  as  man  is  dependent  upon 
his  fellow  men,  just  as  eight  players  on  a  baseball  team  are 
dependent  upon  how  the  ninth  player  plays  the  game,  just 
as  the  work  of  a  class  is  dependent  upon  the  cooperation  of 
the  individual  members,  so  in  the  body,  cells  in  one  place 
are  dependent  upon  the  action  of  other  cells  forming  some 
other  part  of  the  body  and  doing  a  different  sort  of  work. 
The  muscle  cells  cannot  act  unless  the  nerve  cells  do  the 
work  of  sending  nerve  impulses ;  the  nerve  cells  cannot  send 
and  receive  impulses  unless  the  heart  and  lung  cells  do  the 
work  that  is  expected  of  them.  This  interdependence  of  cells 
upon  other  cells  and  of  men  upon  other  men  is  very  important. 
Similarity  between  the  human  body  and  a  city.  —  In  com- 
paring the  city  with  an  animal  such  as  man,  it  will  be  noted 
that  the  construction  of  the  city  and  the  way  its  work  is 
carried  on  resemble  the  body  and  the  activities  of  its  cells. 
The  city  proper  is  composed  of  buildings  that  serve  definite 
purposes ;  the  body  is  made  up  of  a  great  number  of  distinct 
cells  which  perform  special  tasks.  The  stores  on  the  out- 
skirts of  the  city  obtain  their  supplies  from  the  wholesale 
district  by  the  established  channels  of  trade  and  commerce ; 
the  body  cells  receive  their  nutritive  supply  through  the 
blood  channels  which  run  past  the  great  digestive  tract  and 
respiratory  tract.  The  blood  with  its  millions  of  red  blood 
cells  transporting  life-giving  oxygen,  and  with  its  plasma, 


The  Cells  of  the  Body  9 

carrying  life-giving  food,  resembles  a  continuous  chain  of 
auto  trucks  transporting  the  necessities  of  life  to  the  out- 
lying population.  The  waste  products  are  carried  by  the 
blood  to  the  kidneys,  skin,  and  lungs  —  organs  which  serve 
to  remove  this  waste  material.  So  in  a  city  the  "  white 
wings  "  gather  the  ashes,  rubbish,  and  garbage  and,  carrying 
it  to  the  disposal  plant  or  scows  in  the  river,  perform  for  the 
city  the  function  of  excretion. 

The  city  is  controlled  and  directed  by  officers  elected  by 
the  people.  These  officers  must  provide  for  the  life  and 
development  *  of  the  people,  not  only  with  reference  to  what 
they  need  in  the  way  of  food,  protection,  and  recreation,  but 
also  with  reference  to  what  other  cities  are  doing  in  pro- 
viding for  man  the  best  opportunities  for  life.  In  similar 
fashion,  the  body  is  controlled  and  directed  by  the  nervous 
system,  which  constantly  receives  messages  from  all  the 
cells  of  the  body.  To  .these  messages  it  responds  and  pro- 
vides the  necessities  of  life.  It  also  responds  to  messages 
from  other  men.  In  this  way,  man  and  city,  both,  in  co- 
operation with  other  groups  and  led  by  high  ideals,  achieve 
the  best  development. 

GLOSSARY 

Carbon  Dioxide.  —  A  gas  having  the  composition  of  two  molecules 
of  oxygen  in  combination  with  one  of  carbon.  It  is  heavy, 
colorless,  and  incombustible.  It  is  produced  in  the  decay 
of  animal  and  vegetable  matter  and  in  the  bodies  of  animals 
during  activity. 

Conductivity.  —  Ability  to  carry  heat  or  electricity.  In  nerves, 
it  is  the  ability  to  transmit  stimuli  from  one  part  of  the  body 
to  another. 

Contractility.  —  Power  to  change  the  shape,  to  shorten,  in  the  case 
of  a  muscle.  In  single  cells,  the  shortening  in  one  direction 
produces  an  increase  in  diameter  in  the  opposite  direction. 

Degeneration.  —  The  change  in  the  chemical  constitution  of  the  cells 
from  a  complex  to  a  simpler  chemical  form. 


io  Healthful  Living 

Development.  —  A  series  of  changes  by  which  the  body  progresses 
from  a  lower  to  a  higher  type  of  being.  Growth  may  best 
be  thought  of  as  an  increase  in  substance;  development 
refers  to  the  organization  of  that  substance. 

Disease.  —  The  general  term  for  any  deviation  from  health.  It 
may  be  caused  by  destruction  of  essential  body  cells,  or  by 
poisoning  so  that  the  cells  are  unable  to  function  properly. 

Globule.  —  A  small  spherical  structure. 

Growth.  —  The  process  of  increasing  in  size.  It  is  to  be  dis- 
tinguished from  development,  which  refers  to  organization  of 
the  mass. 

Irritability.  —  The  responsiveness  that  living  matter  shows  to 
more  or  less  rapid  changes  in  external  conditions,  manifested 
by  motion,  change  of  form,  and  in  other  ways. 

Metabolism.  —  The  act  or  process  by  which  on  the  one  hand  food 
is  built  up  into  living  material,  and  by  which  on  the  other 
hand  the  living  matter  in  protoplasm  is  broken  down  into 
simple,  waste  elements  for  removal  from  the  body.  Some- 
times the  building  up  of  food  into  protoplasm  is  called 
anabolism;  the  breaking  down  into  simple  waste  products, 
katabolism. 

Multicellular.  —  Many-celled. 

Nucleolus.  —  A  small,  well-defined  particle  found  within  the  nu- 
cleus of  the  cell.  It  is  easily  stained  with  staining  fluids,  and 
because  it  absorbs  stain  more  readily  than  the  nucleus,  it  is 
distinguished  without  difficulty. 

Nucleus.  —  A  round  or  oval  body  within  the  protoplasm ;  it  is 
surrounded  by  a  delicate  membrane.  The  nucleus  is  respon- 
sible for  the  vital  functions  of  the  cell. 

Organism.  —  A  body  composed  of  different  organs  or  parts,  per- 
forming functions  that  are  mutually  dependent  and  essential 
to  life.  A  single  cell  may  be  considered  an  organism  although 
the  different  parts  are  not  readily  distinguished. 

Ovum.  —  A  cell  produced  by  the  generative  organs,  the  ovaries, 
of  the  female.  It  is  capable  of  producing  a  new  individual. 

Oxygen.  —  In  chemical  terms,  oxygen  is  represented  by  the  letter 
O.  It  is  a  colorless,  tasteless,  odorless  gas,  very  abundant 
in  nature.  It  was  first  discovered  by  Priestley  in  England. 
It  combines  with  other  chemical  elements,  and  all  mechanical 
power  obtained  from  combustion,  whether  through  the  medium 
of  steam,  electricity,  or  muscular  action,  depends  upon  oxida- 
tion. 


The  Cells  of  the  Body  n 

Properties.  —  Distinguishing  characteristics.  Qualities  that  make 
the  object  what  it  is. 

Protoplasm.  —  The  semiliquid,  more  or  less  granular  substance 
that  forms  the  principal  portion  of  an  animal  or  vegetable 
cell.  It  is  present  in  all  organized  bodies  and  so  Huxley 
called  it  "  the  physical  basis  of  life." 

Reproduction.  —  The  process  by  which  an  animal  or  plant  gives 
rise  to  another  of  its  own  kind  and  therefore  the  process  by 
which  life  is  continued  from  one  generation  to  another. 

Specialization.  —  The  setting  apart  of  an  organ  or  part  for  per- 
forming a  particular  function. 

Spermatozoon.  —  The  germ-cell  of  the  male  which  joins  with  the 
ovum  in  reproducing  a  new  individual.  These  cells  are  com- 
posed of  protoplasm  and  illustrate  specialization. 

Tissue.  —  An  arrangement  of  cells  in  a  definite  manner.  The 
cells  are  grouped  in  masses  of  one  kind. 

Unicellular.  —  One-celled.     Consisting  of  a  single  cell. 


CHAPTER   II 

TISSUES 

I.    Kinds  of  Tissues. 
II.    Epithelial  Tissues. 

Mucous  and  serous  membranes 
Glands 
The  teeth 
The  skin 
The  hair 
The  nails 
III.    Indications  of  Good  Health. 


Kinds  of  tissues.  —  In  all  but  the  single-cell  type  of  life 
the  body  is  composed  of  an  arrangement  of  many  cells. 
These  cells,  as  we  have  learned,  are  of  different  kinds.  They 
have  come  from  a  single  cell  but  in  developing  they  have 
specialized  in  order  to  do  a  certain  kind  of  work.  From  the 
cells  there  has  developed  a  substance  which  lies  outside  the 
cell  wall ;  it  is  known  as  the  intercellular  substance. 

Now,  it  is  a  very  important  fact  that  certain  tissues  arc 
more  highly  specialized  than  others.  Such  tissues  become 
more  highly  developed  because  they  have  a  more  important 
work  to  do.  It  is  generally  understood  that  nerve  tissue 
is  more  valuable  than  the  tissue  that  forms  our  nails  or  our 
hair.  Nevertheless,  some  foolish  people  take  better  care  of 
their  hands  than  they  do  of  their  nervous  system.  Physi- 
ology should  teach  us  what  is  relatively  more  important. 

In  the  construction  of  the  body  different  types  of  tissues 
Are  used.  By  analogy,  the  body  may  be  likened  to  a  house, 
where  sills,  rafters,  plates,  and  studding  are  used  for  the 


Tissues 


frame.  Other  material  different  in  shape  and  form  is  used 
to  fashion  the  separate  rooms,  to  provide  a  covering,  and  to 
make  the  place  habitable.  So  the  tissues  in  the  body  serve 
particular  purposes.  We  say,  therefore,  that  the  muscle 
and  the  nerve  tissues  serve  the  body  in  acting  and  thinking  ; 
the  epithelial  and  the  connective  tissues  afford  protection 
and  support  to  the  muscle  and  the  nerve  tissues.  Of  these 
four  tissues,  the  epithelial  and  the  connective  may  be  re- 
garded as  elementary,  being  common  to  both 
plants  and  animals.  Muscles  and  nerve 
tissues  are  seen  only  in  animals.  The  four 
kinds  of  tissues,  therefore,  are  epithelial,  con- 
nective, muscular,  and  nervous. 

Epithelial  tissues.  —  Covering  the  surface, 
and  lining  every  cavity  and  tube  of  the  body 
is  a  tissue  consisting  of  one  or  more  layers  of 
distinct  cells,  forming  what  is  called  epithelial 
tissue.  It  is  very  simple,  consisting  merely 
of  cells  packed  closely  together,  and  united 
by  a  very  small  amount  of  cement  substance 
(something  like  the  white  of  egg),  which 
holds  the  cells  together.  The  cells  may  be 
in  a  single  layer  or  in  many  layers.  .No 
blood-  vessels  pass  into  the  epithelial  tissue  ; 
the  cells  derive  their  nourishment  *  from  the 
blood  exuded  into  the  adjacent  tissues. 

The  epithelial  tissues  may  be  placed,  according  to  their 
function,  in  two  divisions.  One  is  chiefly  protective  in 
character,  such  as  the  skin,  the  lining  of  the  mouth,  trachea, 
and  alimentary  tract.  The  other  kind  of  epithelial  structure 
consists  of  cells  that  contain  highly  active  protoplasm.  These 
cells  are  engaged  in  forming  secretions*  from  food  brought  to 
them  by  the  blood.  Such  are  the  cells  of  the  salivary  glands, 
which  secrete  the  saliva  *  ;  of  the  gastric  glands,  which  secrete 
gastric  juice*  ;  of  the  pancreas,  sweat  glands,  kidneys,*  liver, 


FIG.  6.  —  Two 

gastric  glands. 
Simple  tubular 
glands  such  as 
these  may  be 
likened  to  a  well ; 
the  cells  are  like 
the  bricks  of  the 
well-curb. 


Healthful  Living 


FIG.  7.  —  Cells  forming  a  membrane.  (Mucous 
membrane  of  intestines.)  A  few  cells  (dark)  that 
secrete  mucus  are  shown. 


etc.  This  class  of  epithelial  tissue  is  of  the  greatest  value  in 
removing  waste  from  the  body  and  in  preparing  the  food 
for  use  by  the  body. 

Mucous  and  serous  membranes.*  —  Epithelial  cells,  in  se- 
cretory glands,  within  the  body  produce  powerful  digestive 

juices,  as  in  the 
liver,  stomach 
(Fig.  6),  pan- 
creas ;  or  they 
serve  to  protect 
passageways  and 
cavities  (Fig.  7) 
with  a  secretion 
whose  function  is 
chiefly  to  lubricate  the  part.  All  cavities  *  to  which  air  has 
access,  as  the  mouth,  stomach,  and  lungs,  are  lined  with  one 
or  more  layers  of  closely  packed  epithelial  cells,  called 
mucous  membrane  (Figs.  7,  8).  All  cavities  from  which 
the  air  is  cut  off,  as  the  heart,  are  called  serous  cavities,  and 
have  a  lining  of  epithelial  cells 
forming  what  is  called  a  serous 
membrane. 

These  membranes  secrete  a  lu- 
bricating fluid.  The  fluid  formed 
by  the  mucous  membrane  is  called 
mucus ;  that  formed  by  the  serous 
membranes  is  called  serum.  The 
line  where  the  skin  and  the  mucous 
membrane  of  the  lips  join  can  be 
plainly  seen,  as  the  latter  mem- 
brane is  so  thin  that  the  color  of  the  blood  shows  through  it. 
Glands.  —  Glands  (Figs.  9-13)  are  always  lined  with  epi- 
thelial cells,  which  form  a  secretion.  These  glands  vary 
in  shape ;  some  being  tubular,  others  bag-shaped.  The  cells 
of  the  gland,  in  their  own  distinctive  way,  make  use  of  the 


FIG.  8.  —  Epithelial  cells 
lining  the  mouth. 


Tissues 


various  chemical  substances  in  the  blood,  so  that  one  gland 

secretes  oil,  another  perspiration,*  another  saliva,  another 

gastric  juice,  etc.     The  kidneys  are 

important    glands    which    resemble 

some  of  the   glands  of  the  skin  in 

that  they  secrete  injurious  substances 

that    must    be    removed    from    the 

system.     Secretion  is  the  name  given 

the  various  fluids  formed  by  glands.       FIG    9  —  A      t    ical 

If  this  fluid  is  waste  to  be  removed,    structure    of    a    mucous 

it    is    Called    an    excretion.*  membrane  with  two  layers 

of    epithelial     cells,    a,    6, 
Secretion    by    glands    IS    not    Sim-     c,    the    connective    tissue 

plv   a    process    of    beneath'   with   ^   blood- 

^  ,  vessels ;   and  /,  connective 

SOakmg    Or    Sifting     tissue  cells.     B,  the  same 

through.  The  cells    with  one  layer  of 


resting  on  b,  the  so-called 
of  these  glands  are     basement  membrane. 

wonderful    little 

chemical  laboratories   and  they  produce 
FIG.  10.— A  simple  the  different  secretions  from  the  blood  in 
tubular   gland   with  their  own  way.     Moreover,  by  the  aid  of 

blood-vessel.          The  ,  r 

letters,  a,  b,  c,  and  e  the  secretory  nerves,  they  can  tor  a  time 
refer  to  the  same  struc-   regulate  the  amount  of  secretion  regard- 

tures  as  shown  in  Fig.    ,  .  ,.  ,  ,        ,      .        -,    ,  • 

9.  less  of  the  quantity  of  blood  circulating 

around  them,  although  usually  the  amount 
of  secretion  is  greatly  influenced  by  the  supply  of  blood 
in  the  skin  (Chap.  XII).  Sometimes 
the  skin  is  hot  from  the  abundance 
of  blood  flowing  through  it,  as  dur- 
ing a  fever,  but  it  is  dry  then,  as 
well  as  hot,  because  the  sweat  glands 
are  not  active.  At  times,  under  the 
influence  of  excitement  or  fear,  a 
person  breaks  out  in  a  profuse  perspi- 
ration,  which  is  cold,  however,  for 

there  is  little  blood  in  the  skin.  the  gland.  Namea.&.andc. 


i6 


Healthful  Living 


FIG.  12.  —  A  sac- 
like  gland. 


The  teeth.  —  The  teeth  are  developed  from  the  same  kind 

of  tissue  (epiblastic  *)  that  produces  mucous  membrane, 
glands,  and  skin.  These  struc- 
tures, like  the  hair  and  nails, 
arise  from  papillae*  in  the 
dermis  of  the  skin.  A  tooth 
growing  from  epithelial-form- 
ing cells  extends  down  in  a 

depression  in  the  jawbone,  called  a 

socket,*  and  is  held  in  place  largely 

by   the   tightness    with    which    the 

root,   or   lower   part,   fits   into   the 

socket.      The   visible    part    of    the 

tooth  is  called  the  crown. 

Permanent  Teeth.  —  A  complete 

set  of  teeth   in   adults   consists  of 

sixteen  in  each  jaw  or  thirty-two  in 

all.     They  are  named  according  to 

their  form  and  the  uses  to  which       FlG,  .13- -A  racemose  or 

branching  gland,  part  only 

they  are  adapted.  There  are  eight  being  shown.  Name  the 
(Fig.  14)  in  each  quarter  of  the  ^ indicated  b^  «•  &-  c- 
mouth;  and  if  the  names  of  the 

eight  in  one  quarter  are  learned,  you  know  the  names  of 
the  thirty-two,  since  they  are  designated  by  the  same 

names,  in  the  same 
order,  in  each  quar- 
ter of  the  mouth. 
Looking  then  at  the 
teeth  in  one  half  of 
one  jaw  and  naming 

FIG.  14.  —  Teeth  from  one  side  of  the  lower    them    in     order     from 


are  two  incisors,  one 
canine,  two  bicuspids,  and  three  molars.  How  many  of  each 
kind  are  found  in  the  whole  mouth  (Fig.  14)  ? 


Tissues  17 

The  eight  teeth  in  front  are  for  the  cutting  of  the  food,  and 
hence  are  called  incisors,  or  cutters.  They  have  chisel- 
like  edges.  Do  the  edges  of  the  upper  and  lower  teeth 
usually  meet  in  the  mouth,  or  do  they  miss  each  other  like 
the  blades  of  scissors?  The  incisors  are  very  long  in  gnaw- 
ing animals  such  as  rats  and  squirrels.  Next  to  the  two 
incisors  in  each  quarter  of  the  jaws,  comes  one  canine,  so 
called  because  the  corresponding  tooth  in  the  jaws  of  dogs 
is  well  developed.  In  cats,  tigers,  dogs,  and  other  flesh- 
eating  animals,  it  is  suited  for  tearing.  It  has  only  one  root, 
but  that  is  a  long  one.  The  two  upper  canines  are  fanci- 
fully called  the  "  eye  teeth,"  and  the  two  lower,  the  "  stomach 
teeth."  Next  in  order  behind  the  canines  are  the  two  bi- 
cuspids, which  are  grinding  teeth.  Their  crowns  are  broad. 
Last  of  all  come  the  three  large  grinders,  called  molars.  Are 
the  grinding  surfaces  of  the  molars  smooth  or  rough  ?  Are 
they  like  or  unlike  the  surfaces  of  the  bicuspids  ?  The  last 
molar  in  each  jaw  is  called  the  wisdom  tooth,  because  it  does 
not  come  until  the  person  is  supposed  to  have  reached  years 
of  discretion.  Activity  is  the  law  of  life,  and  the  wisdom 
teeth  are  so  far  back  in  the  mouth  that  they  are  not  much 
used ;  therefore,  they  do  not  usually  remain  so  long  as  the 
others. 

Milk  Teeth.  —  Milk  teeth  are  the  first  teeth  to  appear. 
The  teeth  just  described  are  those  of  the  permanent  set. 
The  first  or  temporary  set  of  teeth  —  also  called  the  milk 
teeth  —  consists  of  teeth  the  same  in  name  and  number  as 
those  of  the  permanent  set  except  that  the  three  large  molars 
in  each  half  of  the  jaw,  twelve  in  all,  are  lacking;  so  there 
are  twenty  teeth  in  the  temporary  set  (Fig.  15).  The  milk 
teeth  come  in  the  first  two  years  of  life,  and  begin  in  the 
sixth  or  seventh  year  to  be  pushed  out  and  replaced  by  the 
permanent  set.  They  are  all  gone  by  the  twelfth  year.  On 
the  other  hand,  the  presence  of  the  milk  teeth  is  important 
in  the  development  of  the  jaw.  If  a  milk  tooth  remains  so 
c 


i8 


Healthful  Living 


long  as  to  cause  the  tooth  of  the  second  set  to  grow  out  of 
place,  the  first  tooth  should  be  removed.  If  the  milk  tooth 
decays,  it  should  be  filled,  and  if  the  filling  comes  out  it  should 
be  replaced  by  the  dentist ;  the  milk  teeth  are  an  important 


FIG.   15.  —  Diagram  of  temporary  and  permanent  teeth,  showing  only 
the  parts  outside  the  gum  line. 

stimulant  for  the  proper  development  of  the  permanent  teeth, 
the  jaws,  and  the  bones  of  the  face. 

Parts  of  a  Tooth.  —  The  main  part  of  the  body  of  a  tooth 
is  dentine  *  (Fig.  16) .  The  dentine  of  the  teeth  of  elephants 
and  other  large  animals  is  the  ivory  of  commerce.  It  is 
commonly  used  to  make  piano  keys,  fans,  and  many  novelties. 
In  the  central  part  of  the  dentine  is  a  space  called  the  pulp  * 
cavity.  The  soft  substance,  called  the  pulp,  contains  the 
nerves  and  blood  vessels,  which  enter  at  the  tip  of  the  root. 
In  the  socket,  the  dentine  is  covered  by  cement ;  above  the 
socket  it  is  covered  by  enamel,  a  substance  harder,  denser, 
and  more  shining  than  the  dentine. 

The  enamel  wears  off  of  the  top  of  the  crown  between 
the  twentieth  and  thirtieth  years.  Although  the  dentine 


Tissues 


is  exposed  through  the  wearing  or  breaking  of  the  enamel, 
it  will  last  for  years  without  decaying,  but  it  is  more  likely 
to  decay  than  the  enamel.  We  should  never  run  the  risk 
of  breaking  the  enamel  by  crushing  hard  candies  or  cracking 
nuts.  A  tooth  should  never  be 
pulled  if  it  can  be  saved  by  being 
filled ;  for  pulling  a  tooth  means 
not  only  the  loss  of  one  tooth,  but 
the  end  of  the  usefulness  of  the  tooth 
opposite  to  it,  and  imperfect  chew- 
ing in  that  part  of  the  mouth. 
Losing  a  tooth  is  equivalent  to  los- 
ing a  part  of  life. 

Hygiene  of  the  Teeth.  —  Decay 
of  the  teeth  is  caused  (1)  by  using 
only  soft  food  which  requires  no 
pressure  of  the  teeth  while  chewing 
it;  (2)  by  particles  of  food  that 
lodge  between  the  teeth  and  become 
quickly  decomposed  *  in  the  warm, 
moist  mouth ;  (3)  by  the  collection 
of  tartar  on  the  teeth.  This  is  a 
yellowish  deposit  that  forms  on  the 
teeth  when  they  are  not  kept  clean'. 
(4)  Constant  nibbling  of  candy 

causes  injury  to  the  teeth  through  the  fermentation  of  the 
sugar  left  in  the  mouth. 

In  cleaning-  the  teeth,  the  toothbrush  should  be  rubbed 
up  and  down  as  well  as  across  the  teeth.  Most  tooth  powders 
are  made  from  chalk  as  a  base ;  and  fine  precipitated  chalk* 
is  considered  perfectly  satisfactory  for  cleansing  the  teeth. 
The  teeth  should  be  cleansed  at  least  twice  a  day  and  always 
before  going  to  bed  at  night.  The  teeth  should  be  examined 
once  a  year  by  a  dentist,  and  the  cavities  promptly  filled. 
Adenoids*  should  not  be  allowed  to  deform  the  jaw  and  so 


FIG.  16.  —  Vertical  sec- 
tion of  a  bicuspid  tooth, 
magnified. 


20 


Healthful  Living 


produce  crooked  teeth  (Fig.  17).     It  may  be  necessary  to 
have  adenoids  and  tonsils  removed. 


FIG.  17.  —  Casts  of  the  upper  jaw  of  two  children  twelve  years  old. 
The  left  one  shows  typical  narrowing  of  the  arch,  overlapping  of  the  teeth, 
and  elevation  of  the  palate  due  to  adenoids.  The  right  one  is  that  of  the 
jaw  of  a  healthy,  well-built  child.  (Drawn  from  photograph  by  Dr.  Frank 

Mathews.) 

The  Department  of  Health  of  the  City  of  New  York,  in  an 
effort  to  help  the  children  in  the  schools  to  have  better  teeth, 
has  issued  the  following  instructions  to  parents  : 

DEPARTMENT    OF    HEALTH 

THE  CITY  OF  NEW  YORK 
Instructions  to  Parents  Regarding  the  Care  of  the  Mouth  and  Teeth 

The  physical  examination  of  school  children  shows  that  in 
many  instances  the  teeth  are  in  a  decayed  and  unhealthy  condi- 
tion. 

Decayed  teeth  cause  an  unclean  mouth.  Toothache  and  disease 
of  the  gums  may  result. 

Neglect  of  the  first  teeth  is  a  frequent  cause  of  decay  of  the 
second  teeth. 

If  a  child  has  decayed  teeth,  it  cannot  properly  chew  its  food. 
Improperly  chewed  food  and  unclean  mouth  cause  bad  digestion, 
and  consequently  poor  general  health. 

If  a  child  is  not  in  good  health,  it  cannot  keep  up  with  its  studies 


Tissues  21 

in  school.  It  is  more  likely  to  contract  any  contagious  disease, 
and  it  has  not  the  proper  chance  to  grow  into  a  robust,  healthy 
adult. 

//  the  child's  teeth  are  decayed,  it  should  be  taken  to  a  dentist  at  once 

The  teeth  should  be  brushed  after  each  meal,  using  a  tooth 
brush  and  tooth  powder. 

The  following  tooth  powder  is  recommended : 

2  oz.  powdered  precipitated  chalk. 

%  oz.  powdered  castile  soap.* 

1  dram  powdered  orris  root.* 

Thoroughly  mix. 

This  prescription  can  be  filled  by  any  druggist  at  a  cost  not  to 
exceed  fifteen  cents. 

The  child  should  take  the  tooth  brush  and  powder  to  the  school 
and  receive  instructions  from  the  nurse  as  to  their  proper  use. 
Issued  by  Order  of  the  Board  of  Health 

The  skin.  —  We  have  learned  that  epithelial  cells  form 
mucous  and  serous  membranes,  teeth,  and  secreting  glands. 
They  also  form  the  skin  covering  the  body,  and  from  these 
skin  cells  there  develop  the  hair  and  the  nails.  The  thick- 
ness of  the  skin  is  due  to  the  great  number  of  cells  composing 
it.  These  cells  are  arranged  in  a  definite  manner,  in  two 
layers,  the  dermis  and  epidermis. 

The  outer  layer,  or  epidermis,  rests  on  the  inner  layer, 
the  dermis  (Fig.  18).  The  dermis  is  called  the  true  skin. 
The  epidermis  is  composed  of  a  mass  of  cells  held  together 
by  a  cement  substance.  Those  near  the  surface  are  hard 
and  flattened ;  those  deeper  down,  near  the  dermis,  are 
round  and  soft.  The  lowest  layers  contain  a  pigment*  con- 
sisting of  minute  grains  of  coloring  matter.  The  varying 
amount  of  this  pigment  present  causes  the  difference  in  hue 
of  the  blonde  and  brunette  and  the  light  and  dark  races. 
Freckles  are  due  to  an  increase  of  pigment  in  patches  of 
neighboring  cells.  Some  persons  lack  the  pigment  entirely ; 
their  hair  and  skin  are  white,  the  eyes  pink.  They  are  called 
albinos. 


22 


Healthful  Living 


The  Dermis.  —  The  main  part  of  the  skin  is  the  dermis ; 
it  is  chiefly  a  network  of  fibers.  This  is  the  part  of  the  skin 
of  animals  that  is  tanned  for  leather.  Did  you  ever  notice 

the  fibrous  appear- 
ance in  the  leather  of 
a  shoe  that  has  be- 
come much  worn  ? 
Which  side  of  leather 
is  smooth,  the  side 
covered  by  epidermis, 
or  the  other  side? 
The  dermis  is  con- 
nected with  the  body 
beneath  by  a  loose 
tissue  consisting  of 
fibers  interwoven  with 
cells  of  fat  (Fig.  18). 
This  tissue,  together 
with  the  skin  itself, 
partly  conceals  the 
outlines  of  the  mus- 
cles beneath.  Yet 
artists  study  the 
muscles  carefully,  as 
their  shape  shows 
faintly  through  the 
skin  and  gives  a 
key  to  the  human 
figure. 

The  outer  surface  of  the  dermis  grows  into  numerous  little 
projections  called  papillae.  If  its  covering  of  epidermis 
were  taken  off,  the  dermis  would  appear  somewhat  like 
coarse  velvet  because  of  its  unevenness  ;  for  the  prominences 
or  papillae  appear,  in  a  cross  section  of  the  skin,  under  the 
microscope,  buried  beneath  the  cells  of  the  epidermis,  like 


Sweat 
G/and3 


•  Nutr/ent  Artery 

FiG.  18.  —  Sectional  view  of  the  skin,  mag- 
nified. Find :  oil  (sebaceous)  gland,  sweat 
gland,  sweat  duct,  hair  bulb.  Compare  thick- 
ness of  epidermis,  dermis,  and  subcutaneous 
tissue. 


Tissues 


23 


a  tiny  mountain  range.  As  the  epidermis  fills  up  the  valleys 
between  them,  the  papillae  do  not  show  plainly  on  the  sur- 
face of  the  skin.  However,  on  the  palm  of  the  hand  and 
fingers,  where  the  papillae  are  especially  numerous,  they  are 


N.  B.-Do  not  write  on  this  side  of  the  sheet. 


Classification  JVb. 
RIGHT  HAND. 


ILD  ON  THIS  LINE  I 


"LEFT  HAND. 


FIG.   19.  —  The  finger  prints  of  the  right  and  left  hand, 
is  distinctive  for  each  individual. 


The  marking 


crowded  into  rows,  their  positions  being  shown  by  the  parallel 
ridges  seen  on  the  epidermis  of  the  palm.  These  markings  are 
very  distinct  on  the  palm.  Moisten  the  index  finger  and  notice 
that  an  imprint  of  the  finger  shows  when  pressure  is  made  on 
white  paper  (Fig.  19) .  Under  what  conditions  are  finger  prints 
of  service  ?  Within  the  papillae  are  found  the  ends  of  nerves 
and  loops  of  small  blood  vessels  called  capillaries*  (Fig.  18). 


24  Healthful  Living 

Epidermis.  —  The  cells  of  the  epidermis  which  lie  next 
to  the  dermis  are  living  cells.  They  are  kept  alive  by 
nourishment  brought  by  the  liquid  portion  of  the  blood  in 
the  blood  vessels  of  the  neighboring  papillae.  These  cells 
grow  and  when  they  have  matured  they  divide  and  produce 
new  cells.  The  multiplication  of  the  cells  would  cause  the 
epidermis  to  increase  greatly  in  thickness,  were  not  the  outer 
cells  constantly  worn  away  by  friction.  This  happens  the 
more  easily  because  the  outer  cells  are  dead  cells.  The  new 
cells  forming  beneath  push  them  so  far  away  from  the  dermis, 
that  nourishment  from  the  blood  no  longer  reaches  them, 
and  they  die. 

By  this  constant  loss  and  renewal,  the  body  always  has  a 
comparatively  new  outer  skin.  Even  on  the  scalp,  which  is 
partly  protected  from  friction,  the  flat  dry  cells  are  constantly 
coming  off.  If  there  is  much  oil  on  the  scalp,  the  cells  stick 
together  and  form  flakes  called  dandruff.  This  physiological 
shedding  of  the  cells  of  the  epidermis  is  to  be  aided  by  bathing 
the  skin  and  shampooing  and  brushing  the  hair. 

Organs  of  the  Skin  and  Their  Functions.  —  Lodged  among 
the  fibers  of  the  dermis  and  supported  by  them  are  (1)  a  fine 
network  of  blood  vessels ;  (2)  a  fine  network  of  nerves ; 
(3)  several  million  sweat  glands ;  (4)  a  great  number  of  oil 
glands.  Suppose  you  were  to  stick  a  pin  into  the  dermis. 
The  pin  would  first  pass  through  the  epidermis.  After 
entering  the  dermis  there  would  be  two  signs  that  certain 
structures  had  been  encountered.  What  are  these  structures  ? 
What  signs  would  appear? 

The  blood  vessels  in  the  skin  are  fine  tubes  which  carry  the 
blood  supply  to  and  from  the  skin.  These  vessels  have 
muscles  in  their  walls,  and  when  stimulated  through  the 
nerves  of  the  skin,  the  vessels  change  their  size.  Warmth 
causes  an  increase  in  size  of  the  vessel  and  more  blood  is 
brought  to  the  skin ;  cold  causes  a  decrease  in  size  and  the 
opposite  effect  is  produced. 


Tissues 


The  nerves  of  the  skin  serve  two  main  functions.  One 
function  is  to  control  the  size  of  the  vessels  by  responding 
to  changes  in  temperature ;  the  other  is  to  make  us  aware 
of  the  character  of  things  we  touch.  The  nerves  of  the  skin 
of  the  fingers  in  this  latter  function  are  more  sensitive* 
than  those  in  any  other  part  of  the  body. 

The  sweat  glands,  or  perspiratory  glands  are  little  tubes, 
lined  with  epithelial  cells,  which  pass  through  the  epi- 
dermis and  down  into  the  dermis.  The  tube  is  coiled 


FIG.  20.  —  Coiled  end  of  a  sweat  gland,  epidermis  not  shown,  a,  the 
coil ;  6,  the  duct ;  c,  network  of  capillaries.  The  gland  and  capillary  net- 
work are  shown  separated  and  combined  to  indicate  how  completely  the 
organ  is  supplied  with  blood. 

into  a  ball  in  the  true  skin,  where  it  is  surrounded  by  a  net- 
work of  capillaries  (Fig.  20).  Its  course  through  the  epi- 
dermis is  spiral  like  the  turns  of  a  corkscrew.  Its  opening 
on  the  surface  is  called  a  pore.  The  coiled  part  is 
supplied  with  nerves  which  stimulate  the  cells  to  secrete 
perspiration.  The  cells  obtain  their  supply  of  material 
from  the  blood,  and  this  supply  is  controlled  by  the 


26  Healthful  Living 

nerves  which  regulate  the  size  of  the  arteries*  leading  to 
the  skin. 

The  sweat  glands  take  up  water  and  various  other  sub- 
stances from  the  blood  and  pour  them  out  on  the  surface  of 
the  epidermis.  The  water  evaporates,  but  the  salt  and 
other  solids  in  the  perspiration  are  deposited  on  the  skin. 
Usually  the  amount  of  perspiration  from  each  gland  is  so 
small  that  it  evaporates  as  soon  as  it  reaches  the  surface,  and 
hence  does  not  become  visible.  On  this  account  it  is  called 
insensible  perspiration;  it  becomes  sensible  perspiration 
when  it  is  formed  rapidly  in  warm  weather  or  during  vigor- 
ous exercise.  It  does  not  evaporate  so  quickly  in  a  moist 
atmosphere;  and  those  who  live  near  the  seacoast  or  in 
rainy  regions  show  more  perspiration  than  those  who  live 
in  dry  regions.  The  evaporation  of  this  moisture  on  the 
skin  cools  the  body.  Why  is  the  heat  so  oppressive  on  a 
"  muggy  "  day  ?  The  amount  of  perspiration  averages  about 
one  and  one  half  pints  a  day.  Is  the  skin  more  active  in 
throwing  off  impurities  in  winter,  or  in  summer? 

The  oil  glands,  or  sebaceous  glands,  are  small,  irregu- 
larly-shaped cavities  which  open  into  the  little  pits  from 
which  the  hairs  grow  (Fig.  18).  A  few  oil  glands  open 
directly  upon  the  surface.  They  are  lined  with  epithelial 
cells.  The  cells  deposit  a  kind  of  oil,  which  flows  out  of  the 
mouth  of  the  glands,  renders  the  epidermis  flexible  and  less 
penetrable  by  water,  and  prevents  it  drying  out  by  evapora- 
tion and  cracking  open.  It  is  also  the  natural  "  hair  oil," 
for  softening  the  hair  and  keeping  it  from  becoming  brittle. 
The  oil  glands  of  the  center  of  the  face  are  especially  large 
and  numerous.  When  their  mouths  are  stopped  by  dirt, 
they  become  distended  with  oily  material  and  cause  black- 
heads. Oil  glands  are  absent  from  the  soles  and  palms. 

Protection  of  the  Skin.  —  Clothing  does  not  give  heat 
to  the  body  but  helps  to  prevent  the  escape  of  bodily  heat. 
Linen  and  cotton  absorb  moisture  readily  and  allow  it  to 


Tissues 


27 


evaporate  rapidly.  They  thus  serve,  when  worn  next  to  the 
skin,  to  keep  the  body  dry;  the  evaporation,  however,  if 
very  rapid  may  chill  the  body.  Woolen  absorbs  moisture 
quickly,  but  parts  with  it  slowly,  and,  in  the  case  of  those 
who  perspire  freely,  the 
damp  clothing  next  the 
skin  may  conduct  away 
the  heat.  In  this  way 
woolen  may  seem  cool. 
But  dry  woolen  contains 
much  air  in  the  meshes  of 
the  cloth ;  and  as  this  is  a 
non-conductor  of  heat, 
such  clothing  is  the  warm- 
est of  all,  silk  ranking 
next.  In  cold  climates 
woolen  should  be  worn 
next  to  the  skin,  and 
should  not  be  laid  aside 
until  the  heat  of  summer 
begins.  In  warm 
climates,  like  that 
of  the  Gulf  States, 
it  should  not  be 
worn  next  to  the 
skin  at  all,  even 
in  winter,  except 


;*T*>^:i~ SS 

^5sS«wfe 

y*y<3sir*r? 

'• , /.  i 


nerve 

enafnti 
e,ssner>s 
corpusc/e} 


>•<  *  1  ®'";:f  V  t o/-£ 


FIQ  2L  _,_0i  arrow  indicates  where  the  epidermis 
separates  in  the  formation  of  a  blister.     The  serum 
K-.T    +V>«  -  A^\\      °f  the  blister  exudes  from  the  cells  below,  which 

Dy  tne  very  deli-   are  supplied  by  capillaries, 
cate,  and   it  is  a 

question  as  to  whether  woolen  does  not  do  more  harm  than 
good,  even  to  the  delicate,  as  it  relaxes  and  weakens  the 
skin.  If  it  is  worn  in  such  climates,  with  the  warmth  of 
spring  it  should  be  changed  for  less  relaxing  fabrics.  White 
clothing  reflects  the  heat  of  the  sun ;  dark  clothing  absorbs 
the  sun's  heat.  Rubber  clothing  prevents  moisture  from 


28  Healthful  Living 

penetrating  to  the  body  and  also  prevents  perspiration  from 
escaping.  Bed  clothing  should  not  be  too  heavy.  On 
account  of  the  warm  air  between  them,  two  coverings  are 
warmer  than  one  equal  to  the  two  in  thickness.  The  bed 
clothing  should  be  aired  thoroughly  every  morning. 

When  the  epidermis  is  broken  so  that  the  true  skin  is  ex- 
posed, the  epithelium*  at  the  edge  of  the  break  usually  pro- 
duces new  cells  to  cover  and  heal  the  opening.  But  if  new 
cells  do  not  form,  sufficient  to  bridge  the  opening,  the  dermis 
sprouts  through,  forming  proud  flesh,  which  must  be  scraped 
off  or  cauterized  before  the  epidermis  can  complete  the  heal- 
ing. In  the  case  of  a  blister,  the  lowest  cells  of  the  epidermis 
are  not  removed  (Fig.  21),  hence  the  epidermis  is  readily 
renewed.  Preparations  advertised  to  make  new  skin  over 
a  cut  or  injury  should  not  be  used.  Nature  will  grow  the 
epidermis  if  the  part  is  kept  clean. 

When  the  epidermis  is  weak  the  papillae  over  a  small 
area  sometimes  become  overgrown,  so  that  they  project 
above  the  skin,  and  form  a  wart.  If  it  is  burned  away  with 
acid,  the  epidermis  will  grow  over  the  place.  Why  is  a  wart 
rough?  How  does  it  differ  from  a  mole?  Which  is  more 
likely  to  increase  in  size?  Which  has  more  pigment? 
Which  contains  hairs? 

Hygiene  of  the  Skin.  —  The  scales  of  the  epidermis  are 
gradually  passed  off,  and  with  the  secretions  from  the  oil 
glands  and  surface  dirt,  they  tend  to  form  a  pellicle*  or  coat 
which  interferes  with  the  proper  functioning  of  the  oil  and 
perspiratory  glands.  Bathing  removes  this  pellicle  and  is  of 
great  importance  in  maintaining  a  healthy  skin.  The  cold 
bath  is  intended  to  stimulate  the  body;  the  warm  bath  is 
cleansing.  The  best  time  to  take  the  cold  bath  is  before 
breakfast.  If  this  practice  is  started  in  the  summer,  it  may  be 
continued  through  the  winter  and  not  be  disagreeable  even 
with  very  cold  water.  It  is  best  to  have  a  warm  room  for 
the  bath.  Every  one  may  take  a  cold  bath  because  a  sponge 


Tissues  29 

and  a  basin  of  water  are  the  only  necessary  articles,  although 
a  shower  is  to  be  preferred.  A  warm  bath  is  more  suitable 
on  retiring  than  on  rising ;  it  is  also  more  suitable  for  a 
person  who  is  fatigued.  A  warm  bath  has  a  soothing  effect 
on  the  nervous  system.  The  proper  time  to  bathe  is  just 
before  a  meal  or  at  least  three  hours  after.  Sea-bathing  is 
beneficial  to  the  health  of  the  skin  and  body  in  general,  but 
its  effects  are  due  to  the  enjoyable  exercise  and  pure  out- 
door air  of  the  seashore.  Bathing  in  ocean  or  lake  should 
not  be  prolonged  until  the  bather's  lips  are  blue. 

The  complexion  is  the  outward  expression  of  inner  health. 
A  good  complexion  cannot  be  bought  in  a  box  or  bottle. 
An  artificial  complexion  produced  with  cosmetics  and  face 
powder  is  as  barbaric  and  unnatural  as  the  war-paint  of  the 
savage.  Do  you  know  a  girl  who  paints  and  powders  her 
face?  Is  she  a  wholesome,  healthy  appearing  girl?  A  little 
powder  is  of  value  at  times  on  oily  skins,  but  its  abuse  gives 
an  improper  appearance  and  interferes  with  the  proper 
action  of  the  skin. 

The  face  should  be  washed  at  least  twice  daily.  Cold 
water  should  be  used  because  it  improves  the  circulation, 
it  tones  up  the  elastic  fibers,  and  it  prevents  chapping  and 
roughening  of  the  skin.  Unless  the  face  is  very  dirty  it 
should  be  washed  without  soap.  A  vigorous  washing  with 
cold  water  or  with  warm  water  followed  by  cold  water  will 
remove  the  dirt  in  most  cases.  If  the  skin  is  dry  a  cream 
may  be  used  to  soften  it,  but  it  is  to  be  remembered  that  the 
best  way  to  get  a  beautiful  complexion  is  to  take  proper  care 
of  the  functions  of  the  body  and  to  indulge  in  regular  exer- 
cise, preferably  out  of  doors. 

The  Skin  as  an  Index  of  Health.  —  People  prefer  a  clear 
skin  of  fine  texture  to  a  mottled,  pimply,  coarse  skin.  This 
preference  is  based  partly  on  the  attractiveness  of  the  one 
and  the  repulsiveness  of  the  other.  It  is  also  sustained  by 
the  wholesome  desire  to  appear  well  and  strong,  for  it  is 


Healthful  Living 


recognized  that  the  skin  very  delicately  and  accurately 
shows  the  bodily  condition. 

In  an  effort  to  state  clearly  from  your  own  observation 
the  value  of  health,  answer  the  following  questions : 

1.  Name  five  blessings  in  youth  or  in  later  life  that  result  from 
good  health. 

2.  Name  five  unfortunate  results  of  bad  health. 

3.  Name  five  things  that  people  apparently  value  more  highly 
than  health. 

4.  Think  of  ten  grown  persons.     How  many  of  the  ten  are  in 
sound  health  so  far  as  you  can  tell  ?     What  are  the  signs  ? 

The  hair.  —  It  has  been  learned  that  the  papillae  in  the 
dermis  are  composed  of  epithelial  cells  arranged  in  minute 
projections.  A  hair  is  composed  of 
a  column  of  minute  epithelial  cells 
which  grow  from  a  depression  in  a 
papilla.  This  depression  is  the  hair 
follicle*  or  "root."  Therefore,  a 
hair  grows  from  a  papilla  below  the 
epidermis.  The  only  point  at  which 
the  cells  of  the  hair  and,  therefore, 
the  hair  itself,  are  living  and  grow- 
ing is  at  the  top  of  the  papilla,  deep 
down  in  the  follicle  (Fig.  18).  From 
this  it  is  easy  to  see  that  the  com- 
mon notion  that  cutting  off  the  ends 
of  the  hair,  either  by  shaving  or 

trimming  with  scissors,  causes  it  to  grow  faster  and  stronger, 
is  erroneous.  It  may  stop  the  splitting  of  hairs  and  thus 
prevent  the  wearing  away  of  the  hair.  Of  course,  when  the 
hair  or  beard  is  short  its  growth  is  more  noticeable.  Long- 
hair seems  by  its  weight  to  give  exercise  to  minute  muscles 
in  the  skin  and  to  strengthen  the  flow  of  blood,  thus  adding 
to  the  vigor  of  the  hair.  The  cut  end  of  a  hair  is  nearly 
round  in  the  straight-haired  races,  as  Indians  and  Chinese ; 


FIG.  22.  —  A,  section  of 
hair ;  B,  piece  of  human 
hair,  magnified. 


Tissues  31 

it  is  oval  in  the  wavy-haired  white  race,  and  flattened  still 
more  in  the  kinky-haired  negro  race. 

Hair  is  very  durable  (Fig.  22) ;  that  found  on  Egyptian 
mummies  has  remained  unchanged  through  several  thousand 
years.  It  is  elastic  and  is  said  to  stretch  one  third  of  its 
length  without  breaking.  Hair  absorbs  moisture  readily 
and  for  a  time  its  length  is  considerably  increased  thereby. 
Each  hair  follicle  has  fine  muscles  connected  with  it.  Cold 
or  fear  may  cause  the  muscles  to  contract  and  the  hairs, 
which  are  usually  in  a  slanting  position,  to  stand  erect.  This 
causes  the  hair  to  afford  a  better  protection  to  the  animal 
from  cold  or  blows.  "  Goose  skin,"  which  occurs  if  a  cold 
bath  is  unduly  prolonged,  is  caused  in  the  same  way;  but 
the  hair  on  the  human  skin  is  so  fine  that  the.  goose  skin 
avails  little  against  cold. 

Superfluous  hairs  sometimes  grow  on  unusual  parts  of  the 
face.  To  remove  this  hair  so  that  it  will  not  grow  again, 
the  papillae  at  the  bottom  of  the  follicles  must  be  destroyed. 
This  is  no  easy  matter.  Numerous  "  infallible  remedies  " 
are  advertised,  but  the  only  effective  way  is  by  means  of 
electricity,  used  in  an  electric  needle  by  a  skilled  operator. 

Care  of  the  Hair.  —  The  two  main  causes  for  falling  hair 
are  a  tight  scalp  with  a  poor  circulation  and  the  presence  of 
dandruff.  The  two  important  things  to  attend  to,  there- 
fore, are  massaging  the  scalp  in  order  to  promote  the  circu- 
lation, and  keeping  the  scalp  clean  by  daily  brushing  of  the 
hair  and  shampooing  every  two  or  three  weeks.  Why  does 
the  groom  spend  so  much  time  in  currying  and  brushing  his 
horse  ? 

The  nails.  —  Nails  are  a  growth  of  the  epidermis,  and, 
like  the  epidermis,  only  the  lowest  cells  near  their  roots  are 
alive  and  receive  nourishment.  The  root  of  the  nail  is  in 
a  kind  of  groove  or  fold  of  the  true  skin  at  the  bottom  of 
which  papillae  are  very  numerous.  The  nail  may  be  re- 
garded as  a  very  wide  flat  hair.  The  nail  grows  not  only  at 


Healthful  Living 


-Naif 


Epidet 


Uermis 


FIG.  23.  —  Section  of  nail  and  parts 
beneath. 


its  root  but  along  its  bed,  which  is  of  true  skin  (Fig.  23). 
Hence,  "its  thickness  increases  as  it  approaches  the  tip.  If 
the  epidermis  is  pressed  back  at  the  root,  the  nail  may  not 
be  perfectly  nourished,  and  a  white  speck  or  flaw  is  formed, 
which  travels  slowly  along  with  the  growth  of  the  nail.  It  is 
said  that  the  nail  is  renewed  in  three  or  four  months.  If 
you  note  the  date  of  the  appearance  of  a  scar  at  the  base 

of  the  nail  and  note  when 
it  has  traveled  to  the  tip, 
you  can  find  whether  this 
is  true.  Find  whether  or 
not  a  nail  is  transparent, 
by  looking  through  the  tip 


of  the  nail,  held  up  to  the 
light.  The  nails  stiffen  the 
ends  of  the  fingers  and  aid 
in  handling  small  objects.  Can  you  pick  up  a  pin  without 
using  the  nails  ?  Corresponding  organs  in  the  lower  animals 
are  claws  and  hoofs. 

In  manicuring  the  nails  a  file  should  be  used.  Cutting 
makes  them  brittle.  Biting  the  nails  is  often  a  sign  of  nerv- 
ousness and  should  be  controlled,  not  only  because  of  the 
unpleasant  habit  but  also  because  of  the  injury  to  the  nails 
themselves.  Proper  care  of  the  body  involves  manicuring 
the  nails  and  this  care  should  be  given.  A  well-groomed 
appearance  increases  one's  self-respect  and  commands  the 
respect  of  others. 

Indications  of  good  health.  —  One*  may  be  not  definitely 
sick  and  yet  lack  the  feeling  of  good  health.  This  is  ex- 
pressed at  times  as  not  being  up  to  "  par."  Health  is  not 
only  a  condition  of  freedom  from  disease  but  also  a  quality 
of  life  and  it  is  to  our  advantage  to  keep  ourselves  at  the 
highest  and  best  level  of  health  attainable.  In  this 
connection  there  are  certain  indications  of  health  that  are 
valuable : 


Tissues  33 

1.  Consciousness  of  feeling  well.     Allied  to  this,  of  course,  is 
the  absence  of  pain. 

2.  Enjoyment  of   activity  of   muscle   and  mind.      One  is  not 
at  the  highest  point  of  efficiency  if  activity  is  not  enjoyed. 

•  3.  Sound  sleep  with  a  feeling  of  being  rested  in  the  morning. 
One  should  be  sleepy  when  tired  out,  and  one  is  in  normal  condi- 
tion in  this  respect  if  he  can  go  to  bed  and  sleep. 

4.  Normal    appetite    and    normal    digestion.     The    power    to 
enjoy  wholesome  food,  to  eat  and  enjoy  a  good  breakfast. 

5.  Power  to  remove  the  waste  of  the  body  without  taking  drugs. 

6.  Poise  and  control  in  the  muscular  movements  of  the  body. 
This  means   the  involuntary  movement   of  breathing   also,   and 
requires  that  the  individual  breathe  calmly,  deeply,  and  regularly. 

7.  Ability  to  accomplish  the  work  that  lies  ahead.     This  does 
not  mean  that  all  work  must  be  successful,  but  there  should  be 
the  feeling  that  there  is  achievement. 

8.  Throughout  all  these  activities,  the  happy,  cheerful  disposi- 
tion is  a  sign  and  indication  of  good  health.     This  does  not  mean 
that  one  .must  go  about  with  a  smile  or  grin  on  the  face,  but  a 
habit  of  meeting  difficult  tasks  without  fear  or  discouragement 
should  be  cultivated. 

These  eight  indications  are  of  value  in  that  they  point  out 
the  way  of  health,  which  is  something  more  than  mere  ab- 
sence of  disease;  it  means  abundant  health  of  such  a  kind 
that  one  can  do  more  work  and  also  give  and  receive  more 
happiness  and  enjoyment  in  the  world. 

APPLIED    PHYSIOLOGY 

Exercise  I 

1.  If  a  hair  is  pulled  out,  what  determines  whether  it  will  grow 
again  ? 

2.  Why  is  linen  used  for  towels  ? 

3.  What  causes  the  hair  to  "  stand  on  end  "  when  a  person  is 
frightened  or  when  an  animal  is  cold  ? 

4.  What   color   of   clothing  is  best   adapted  to  summer?     To 
winter  ? 

5.  How  may  rubber  shoes  make  the  feet  moist? 

6.  State  a  fact  which  shows    that  the  skin  is  a  regulator  of 
temperature 


34  Healthful  Living 

7.  Are  wrinkles  a  sign  that  the  skin  is  too  tight  or  too  large 
and  loose  for  what  it  covers  ? 

8.  In  what  ways  may  a  city  and  the  body  of  man  be  compared  ? 

9.  Describe  the  division  of  labor  in  cells. 
10.   What  are  signs  of  health  in  the  body? 


Exercise  II 

11.  Why  does  the  heat  seem  more  oppressive  in  moist  weather? 

12.  Which  should  usually  wear  warmer  clothing,  a  farmer  or 
a  merchant  ? 

13.  Which  teeth  are  important  for  the  development  of  the  bones 
of  the  jaw  and  face? 

14.  In  what  respect  do  patent  leather  shoes  resemble  rubber 
shoes  ? 

15.  Why  is  baldness  more  common  among  men  than  among 
women  ? 

16.  What  are  the  important  principles  in  the  care  of  the  hair  ? 

17.  Why  is  a  complexion  considered  beautiful  when  it  is  pink 
and  fair  ? 

18.  What  is  the  best  means  of  improving  the  circulation  in 
the  skin? 

19.  Who  is  more  apt  to  have  a  sincere  nature,  a  person  with 
a  clean  face    and    truthful    complexion,   or  one  who  paints  and 
powders  ? 

20.  What  are  the  functions  of  the  skin? 


Exercise  III 

21.  What  are  the  causes  of  decay  of  the  teeth? 

22.  Of  what  use  is  this  information? 

23.  Did  you  ever  know  of  a  case  of  loss  of  health  caused  by 
changing  the  warm  clothing  of  daily  wear  for  the  thin  or  scanty 
dress  of  a  ball  or  party  ? 

24.  Why  should  we  remove  an  overcoat  or  cloak  when  we  go 
into  a  room  ? 

25.  Why  is  cold  water  better  than  warm  water  for  the  daily 
bath? 

26.  Explain  how  the  wearing  away  of  the  outer  cells  of  the 
epidermis  contributes  to  the  cleanliness  of  the  body. 

27.  What  is  the  effect  of  cold  water  upon  the  skin  ? 


Tissues  35 


LABORATORY  EXERCISES 

Experiment  1.    To  study  the  structure  and  arrangement  of  the  cell 
in  an  orange. 

Material.  —  Navel  orange. 

Method  and  observation.  —  Peel  the  orange  and  separate  a  seg- 
ment.    Gently  break  open  a  segment  and  observe  the  cells  filled 
with  juice.     In  terms  of  animal  tissues,  locate  the  cell  wall,  the 
intercellular  spaces,  and  the  protoplasm. 
Experiment  2.    To  study  cellular  structure. 

Material.  —  Onion  (sprouting),  slide,  microscope,  toothpick, 
methylin  blue,  medicine  dropper. 

Method  and  observation.  — 

(a)  Peel  a  thin  piece  of  tissue  from  an  onion  root  and  place  on 
a  slide.  Observe  with  low  and  high  power  and  identify  cellular 
structure. 

(6)  With  a  clean  toothpick  take  a  scraping  of  cells  from  the 
tip  of  the  tongue  or  inside  of  cheek.  Place  scraping  on  slide  and 
add  one  drop  of  methylin  blue.  Allow  the  stain  to  remain  one 
minute  and  then  remove  the  excess  of  stain  by  gently  flushing  the 
slide  with  water  from  a  medicine  dropper.  Cover  with  cover  glass 
and  place  slide  under  microscope.  Identify  cell  wall,  nucleus  and 
protoplasm. 
Experiment  3.  To  study  cells  and  tissues. 

Use  prepared  slides 1  showing  different  tissues  and  exhibit 
these  under  the  microscope.  Let  the  pupils  see  the  main  varieties. 

GLOSSARY 

Adenoids.  —  An  enlargement  of  the  connective  tissue  at  the  upper 

part  of  the  throat  where  the  throat  and  nose  meet. 
Artery.  —  One  of  the  tubes  that  convey  blood  from  the  heart  to 

the  cells  and  lungs  of  the  body. 
Capillary.  —  A   fine,    slender    blood   tube   with   a    hairlike   bore. 

Capillaries  are  the  smallest  tubes  for  conveying  blood.     The 

arteries  terminate  in  capillaries. 
Castile  soap.  —  A  white  hard  soap  made  with  olive  oil.     In  making 

hard  soap  the  alkali  used  is  soda ;  if  potash  is  used  the  product 

is  soft  soap. 

1  Permanent  preparations  of  cells  and  tissues  may  be  obtained  from 
Bausch  and  Lomb  Optical  Company,  Rochester,  New  York. 


36  Healthful  Living 

Cavity.  —  A  hollow  space  within  the  body.  The  term  cavity  is 
used  if  this  space  is  either  actual  or  potential. 

Decompose.  —  A  separation  into  the  chemical  elements  that  make 
it  up.  Used  to  describe  decay  and  disintegration. 

Dentine.  —  The  hard  dense  substance  which  forms  the  major 
part  of  the  tooth. 

Epiblastic.  —  The  outermost  layer  in  the  developing  embryo.  It 
forms  the  skin,  the  hair,  the  teeth,  and  the  nails. 

Epithelium.  —  The  tissues  in  which  the  cells  are  arranged  to  cover 
free  surfaces  and  to  form  the  active  structural  element  of  the 
glands  that  secrete.  The  arrangement  of  the  epithelium  is 
very  orderly;  epithelium  of  the  mouth  can  readily  be  dis- 
tinguished from  the  epithelium  of  the  skin,  stomach,  liver,  etc. 

Excretion.  —  The  discarded  waste  from  the  body.  This  waste 
matter  is  thrown  off  by  the  cells  and  in  doing  so  illustrates  the 
katabolic  aspect  of  metabolism.  Excretion  is  not  to  be  con- 
fused with  secretion,  because,  although  both  are  produced  by 
the  cells  of  the  body,  the  product  of  the  former  contributes 
to  remove  waste,  and  the  product  of  the  latter  is  useful  in 
activities  of  the  body. 

Follicle.  —  A  minute  cavity,  sac,  or  tube. 

Gastric  juice.  —  A  thin  acid  fluid  secreted  by  the  glands  of  the 
stomach.  These  glands  are  composed  of  epithelium  and 
produce  hydrochloric  acid  and  also  pepsin  and  rennin.  These 
substances  form  the  chemical  essentials  in  the  juice  and  are 
responsible  for  its  action. 

Kidneys.  —  Two  organs  situated  in  the  back  part  of  the  abdomen. 
The  cells  are  mainly  of  epithelium  and  secrete  from  the  blood 
as  it  passes  through  the  kidneys  the  waste  that  forms  the 
excretion  known  as  the  urine. 

Membrane.  —  A  thin  sheetlike  structure  composed  of  epithelium 
cells  and  serving  to  line  a  cavity,  tube,  or  follicle. 

Nourishment.  —  That  which  sustains  the  life  and  promotes  the 
growth  of  the  individual. 

Orris  root.  —  The  fragrant,  violet-scented  root  obtained  from 
several  species  of  Iris,  a  plant  with  sword-shaped  leaves  and 
known  in  cultivation  as  fleur-de-lis. 

Papilla.  —  A  small  nipple-like  process. 

Pellicle.  —  A  thin  film. 

Perspiration.  —  The  product  of  the  secretion  activities  of  the  sweat 
glands  in  the  skin.  This  exhalation  is  an  excretion. 

Pigment.  —  Any  substance  that  gives  color  to  animal  or  vegetable 


Tissues  37 

tissues  as  exhibited  in  the  skin,  the  hair,  the  eye,  and  the 
leaves  and  flowers  of  plants. 

Precipitated  chalk.  —  A  heavy,  fine  powder.  It  is  obtained  by  pre- 
cipitating calcium  carbonate.  It  is  much  used  in  tooth 
powders. 

Pulp.  —  The  soft  tissue  composed  of  blood  vessels  and  nerves  and 
found  within  the  cavity  of  a  tooth. 

Saliva.  —  A  tasteless,  odorless,  slightly  viscid,  alkaline  secretion 
of  the  salivary  glands  of  the  mouth. 

Secretion.  —  A  substance  separated  from  the  blood  by  the  cells 
developed  for  that  purpose.  This  substance  plays  some  useful 
part  in  the  body.  It  is  to  be  distinguished  from  the  term 
excretion. 

Sensitive.  —  A  quality  of  being  easily  affected  by  outside  opera- 
tions or  influences. 

Serous  membrane.  —  A  delicate  tissue  composed  of  flattened  cells 
that  line  the  large  cavities  of  the  body.  These  cells  secrete 
a  fluid  called  the  serous  fluid.  It  is  similar  to  the  serum  of 
blood. 

Socket.  —  A  cavity  or  opening  especially  adapted  to  receive  some 
correspondingly  shaped  piece. 

Vein.  —  A  muscular  and  tubular  vessel  that  conveys  blood  to  the 
heart.  It  is  distinguished  from  an  artery  by  having  less 
muscle  and  elastic  tissue  in  its  wall  and  by  carrying  blood  to 
the  heart ;  the  artery  carries  blood  from  the  heart. 


CHAPTER   III 
TISSUES    (Continued) 

I.   Connective  Tissues. 

White  fibrous  tissue 
Yellow  elastic  tissue 
Adipose  tissue 
Cartilaginous  tissue 
Osseous  tissue 
II.   Muscular  Tissues. 

Oxidation  and  muscular  action 

Oxidation  and  burning 

Oxidation  in  the  body  and  in  a  machine 

Points  of  similarity  between  the  human  body  and  a  steam 

engine 
Points   of   difference  between   the  human   body   and   a 

steam  engine 

Muscular  contraction  and  chemical  change 
Alcohol  and  muscular  efficiency 

III.  Nervous  Tissues. 

Nerve  structure 

How  nerves  and  muscles  work  together 

IV.  Building  Good  Tissues. 

The  effects  of  alcohol 
The  effects  of  drugs 
Stimulation  vs.  construction 


Connective  tissues.  —  Connective  tissue  serves  the  body 
by  affording  support  to  its  several  parts.  The  fibrous  tissue, 
which  binds  the  cells  together  and  supports  the  various 
organs,  is  also  called  connective  tissue,  but  it  is  distinguished 
from  the  connective  tissues  in  general  by  the  name  "  white 
fibrous  connective  tissue."  In  some  of  this  tissue  there  are 

38 


Tissues 


39 


yellow  elastic  fibers,  hence  the  name  "  yellow  elastic  con- 
nective tissue  "  is  used.  The  tissues  that  are  to  be  grouped 
under  the  connective  tissue  head- 
ing are : 

1.  White  fibrous  tissue  (Fig.  24). 

2.  Yellow  elastic  tissue  (Fig.  24). 

3.  Adipose  (fatty)  tissue  (Fig.  25).    c 

4.  Cartilaginous  tissue  (Fig.  26). 

5.  Osseous  (bony)  tissue. 

White  fibrous  tissue.  —  White 
fibrous  connective  tissue  consists 
of  cells  that  have  very  small 
nuclei  and  cell  bodies  that  are 
prolonged  into  fibrous  strands 
(Fig.  24).  These  fibers  may  be 
considered  as  a  development  of 
the  cell  (Fig.  24,  c).  They  are 

.      &         . '       .  /  FIG.   24.  —  Connective    tissue 

not    elastic.       IhlS    tissue    lorms     taken    from    beneath    the    skin, 
the    ligaments  *    Structures    that    «•  yellow  elastic  fibers ;   b,  white 

fibers;    c,  cell   which   forms   the 

hold  the  ends  of  bones  together,    kind  of  fiber  shown  in  b. 
making  a  joint. 

Yellow  elastic  tissue.  —  Yellow  elastic  connective  tissue 
is  found  scattered  among  the  white  fibers  (Fig.  24).  It  is 
relatively  large  in  amount  in  the  walls  of  the  blood  vessels, 
and  in  the  firm  part  of  the  ear. 

Adipose  tissue.  —  This  soft  tissue  furnishes  cushions  for 
delicate  organs  like  the  eye,  forms  a  layer  under  the  skin, 
thus  rounding  out  the  form  and  storing  up  food  for  the  use 
of  nerve,  muscle,  and  other  cells.  The  fat  is  first  deposited 
in  the  form  of  minute  globules  in  the  white  connective  tissue 
cells ;  these  globules  gradually  increase  in  size.  Fatty 
tissue  is,  therefore,  nothing  more  than  fat  deposited  in  the 
cell  body  of  white  connective  tissue  (Fig.  25).  What  is 
lard  ?  Tallow  ?  Suet  ?  In  what  tissue  do  these  substances 
lie? 


4o 


Healthful  Living 


Cartilaginous  tissue.  —  Some  parts  of  the  body  require 
tissue  having  something  of  the  rigidity  of  bones,  yet  capable 


White  Fibrous 
'Connective  Tissue 


Protop/asm 


FIG.  25.  —  Fatty  tissue.     Five  fat  cells,  held  together  by  bundles  of 
connective  tissue. 

of  bending  under  pressure.  This  purpose  is  fulfilled  by  the 
elastic  tissue  called  cartilage.  A  piece  obtained  fresh  from  an 
animal  is  seen  to  be  covered  by  a  thin  fibrous  membrane, 
which  is  reddish  because  it  contains  blood  vessels.  When 
this  membrane  is  stripped  off,  the  cartilage  shows  no  sign  of 
redness,  that  is,  it  contains  no  blood  vessels.  Under  the 
microscope,  cartilage  is  seen  to  be  composed  of  cells,  often 
arranged  in  pairs  (Fig.  26),  which  suggests  the  fact  that  they 
have  been  formed  by  the  division  of  one  cell.  The  substance 
between  the  cells  is  the  product  of  the  cells,  has  been  de- 


Tissues  41 

posited  by  them,  and  is  called  the  intercellular  substance  or 
matrix.* 

Cartilage  may  be  readily  felt  in  the  nose  at  the  tip,  and  in 
the  ears.     The  cartilage  of  the  ear  contains  an  abundance 
of  elastic  fibers.    The 
cartilage  between  the    .  ^   ofTwo 
divisions  of  the  ver- 
tebral   column  •  con- 
tains    both     yellow 
elastic     and      white 
fibrous  cells.     It  is,     "*'"* 
therefore,  in  nature, 

7      ,.  ,   ,          i  FIG.  26.  —  Cartilage.     A  thin  section, 

elastic  and  tough.  highly  magnified. 

Osseous     tissue.  — 

Just  as  white  fibrous  tissue  supports  and  holds  in  place 
the  delicate  cells  and  fibers  of  the  organs,  so  bone  and 
cartilage  support  the  complete  organs  and  hold  them  in 
their  places  in  relation  to  one  another.  Cartilage  and 
bone  are  closely  related  as  to  location,  function,  and  de- 
velopment. For  example,  the  flat  bones,  in  infancy,  form- 
ing the  roof  and  sides  of  the  skull,  are  soft  and  flexible,  being 
composed  of  cartilage,  except  for  a  small  patch  of  bone  in  the 
middle  of  each.  As  growth  proceeds,  the  bones  touch  and 
interlock,  replacing  the  cartilage.  If  a  bone  is  broken,  the 
new  part,  as  it  forms,  is  first  cartilaginous  and  afterward  it 
is  replaced  by  true  bone.  Growth  in  length  of  the  bones 
takes  place  in  the  cartilage  at  the  ends  of  the  bones.  A 
person  ceases  to  grow  in  height  at  about  the  age  of  twenty- 
five  on  account  of  the  ossification  of  the  cartilage. 

There  are  machined  for  increasing  one's  height.  They 
work  by  stretching  the  spine.  Many  persons  could  become 
taller  by  standing  and  walking  in  an  erect  posture.  After 
the  ossification  of  the  cartilage  in  bone,  however,  increased 
height  can  only  be  secured  by  making  the  body  more  erect, 
either  by  machines  or  by  exercise. 


42  Healthful  Living 

All  bones  are  covered  by  a  thick  fibrous  tissue  called 
periosteum.*  This  contains  the  blood  vessels  which  pass 
into  the  bone  to  supply  nourishment  and  also  bone  cells 
which  by  development  increase  the  circumference  of  the 
bone. 

Muscular  tissues.  —  The  cells  constituting  the  body  were 
likened  to  a  human  community  or  city.  Such  a  comparison 
helps  us  to  realize  how  complex  is  an  animal  body,  and  how 
wonderful  are  the  processes  of  life.  But  the  relation  be- 
tween the  cells  is  much  closer  than  that  between  the  in- 
dividuals of  a  community.  There  is  a  marked  difference, 
however.  The  human  being  can  move  as  a  whole,  can 
change  place  in  space,  and  can  act  with  the  harmonious 
assistance  of  the  organs  of  the  body.  The  energy  *  stored  in 
the  body  enables  it  to  do  these  things,  and  the  two  tissues  that 
chiefly  expend  the  energy  and  give  us  the  ability  to  do  thinge, 
to  act,  are  nervous  tissues  and  muscular  tissue.  In  me- 
chanical terms,  therefore,  the  body  may  be  called  a  neuro- 
muscular  mechanism.* 

Oxidation*  and  muscular  action.  —  This  energy  in  muscular 
action  arises  from  a  kind  of  combustion*  or  chemical  reaction, 
and  resembles,  in  its  source,  the  energy  of  the  steam  engine. 
That  something  besides  wood  or  coal  is  necessary  to  a  fire 
can  be  shown  by  shutting  off  entirely  the  draught  of  the 
stove.  Fire  and  all  other  forms  of  combustion  depend  upon 
a  process  called  oxidation.  This  consists  in  the  uniting  of 
oxygen,  the  active  element  of  the  air,  with  carbon,*  hydro- 
gen,* and  other  elements  in  wood,  coal,  etc.  Bread,  meat, 
and  other  foods  contain  these  energy  elements  also.  That 
there  is  carbon  in  sugar  can  be  easily  proved  by  charring 
sugar  upon  the  stove,  the  charcoal  thus  produced  being  a 
form  of  carbon.  Complex  organic  *  food  compounds  contain- 
ing these  elements  are  taken  into  the  body  through  the  diges- 
tive organs  and  broken  up  into  smaller  units  which  may  be 
stored  in  the  body  cells  ready  for  union  with  oxygen  when 


Tissues  43 

action  is  needed.  The  oxygen  enters  the  body  through  the 
lungs  and  is  carried  to  the  tissues  by  the  red  blood  cells 
of  the  blood.  Oxygen  is  not  stored  in  the  body  but  is  taken 
in  in  response  to  the  needs  of  the  body  for  oxygen. 

Oxidation  and  burning.  —  The  body  resembles  a  locomotive 
in  having  warmth  and  motion  as  a  result  of  the  union  of 
fuel  and  oxygen ;  but  it  differs  from  the  locomotive,  since 
the  intelligent  engineer  is  an  integral  part  of  it,  and  since  the 
oxidation  in  the  body  is  in  the  presence  of  moisture,  and  so 
gradual  that  it  is  not  a  true  fire  accompanied  by  light.  More- 
over the  body  can  repair  itself  as  it  wears  out,  and  the  engine 
cannot.  The  energy  stored  in  the  body  is  used  more  economi- 
cally than  any  steam  engine  can  use  fuel. 

Oxidation  in  the  body  and  in  a  machine.  —  There  are  points 
of  similarity  and  points  of  difference  between  the  body  and 
the  machine.  Too  often  the  differences  are  not  noted.  The 
human  body  is  very  complex,  and  the  effect  of  any  particular 
process  is  so  profound  that  great  care  must  be  exercised  to 
avoid  stating  too  positively  what  any  effect  will  be.  There 
are  people  who  are  willing  to  state  what  the  effect  of  a  certain 
exercise  on  the  body  will  be,  and  they  talk  about  educational 
exercise  and  hygienic  exercise.  In  most  instances  they  are 
unfamiliar  with  the  real  meaning  of  education  and  hygiene, 
and  they  do  not  appreciate  how  very  difficult  it  is  to  predi- 
cate the  effect  of  any  particular  exercise.  That  the  body 
resembles  a  machine  there  can  be  no  doubt,  but  it  is  quite  as 
important  to  remember  that  there  are  very  important 
differences. 

Points  of  similarity  between  the  human  body  and  a  steam  engine. 

1.  Both  require  fuel. 

2.  Both   transform   energy  from  rough   masses.     The   energy 
in  the  wood  and  coal  is  potential  *  and  in  the  steam  engine  it  is 
changed  into  kinetic  *  energy  in  the  form  of  heat.     The  energy  in 
meat  and  potatoes  and  other  foods  is  potential,  and  by  digestive 
processes  it  is  changed  into  kinetic  energy. 


44  Healthful  Living 

3.  Both  produce  waste  products  and  both  must  have  this  waste 
removed.     It  is  just  as  important  to  keep  the  human  body  free 
from  its  waste  as  it  is  to  keep  the  ashes  out  of  the  furnace  box. 
Many  people  take  better  care  of  the  furnace  in  the  home  than  they 
do  of  the  furnace  in  their  own  body.     This  is  largely  because  of 
ignorance  and  not  because  of  lack  of  interest. 

4.  Both  are  of  complicated  mechanism. 

5.  Both  need  repair.     The  engine  cannot  repair  itself,  but  the 
body  in  many  particulars  can  repair  injuries.     It  is  important 
to  remember  that   the  body  cannot  repair  all  injuries    without 
the  assistance  of  man.     An  inflamed  appendix,*  a  broken  bone, 
cancer,  and  many  other  instances  of  injury  need  the  trained  hand 
and  intelligence  of  the  surgeon.     There  are  people  who  attempt 
to  repair  the  body  by  taking  "  patent  medicine,"  and  yet  they 
will  send  for  a  mechanic  to  repair  the'  broken  pump  or  the  black- 
smith to  repair  the  broken  wheel  of  the  wagon.     These  people 
foolishly  attempt  to  tell  what  is  wrong,  and  to  treat  a  mechanism 
that  is  very  complicated ;   on  the  other  hand,  they  would  not  think 
of  such  procedure  in  repairing  a  simple  mechanism  like  a  pump, 
wagon,  or  automobile. 

6.  Both  need  rest.     Great  industrial  plants  often  have  two 
sets  of  power  engines  so  that  they  can  rest  one  set  on  alternate 
weeks.     Men  are  saying  to-day  that  they  can  do  twelve  months 
work  in  ten  months,  but  they  cannot  do  it  in  twelve.     Rest  is 
needed. 

7.  Both  need  exercise,  activity.     This  similarity  is  very  im- 
portant.    In  each  case  the  right  kind  of  activity  is  essential  for 
the  most  efficient  action. 

8.  Both,  need  intelligent  care.     We  need  to  take  as  good  and  as 
intelligent  care  of  our  bodies  as  the  engineer  takes  of  the  steam  or 
gasoline  or  electric  engine. 

Points  of  difference  between  the  human  body  and  a  steam  engine. 

1.  A  human  body  requires  a  greater  variety  of  fuel.     The  steam 
engine  will  burn  coal  and  will  do  its  best  work  on  that  particular 
kind  of  supply.     The  human  body  will  not  do  its  best  work  on 
meat  or  vegetables  or  nuts  alone. 

2.  A  human  body  is  never  entirely  inactive.     Even  at  night 
when  asleep,  the  human  body  is  working,  carrying  on  the  processes 
which  keep  the  body  alive. 

3.  A  human  body  has  the  power  of  self-development.     On  the 
physical  side  it  starts  with  a  single  cell  and  grows  to  maturity. 
Under  intelligent  direction,  this  growth  may  be  directed  to  produce 


Tissues  45 

a  very  fine  type  of  being.  This  power  of  self-development  make^ 
the  human  body  very  much  more  interesting  than  the  steam  en- 
gine. 

Muscular  contraction  and  chemical  change.  —  How  does 
the  oxidation  of  food  produce  motion?  We  learn  that  the 
amoeba  and  other  one-celled  animals  can  change  their  shapes. 
Many  of  the  cells  of  the  body  have  lost  this  power,  but  the 
muscle  cells  retain  it.  Figures  79,  80,  81  show  various  types 
of  muscle  cells.  They  differ  in  the  shape  of  the  cells  and  to 
some  extent  in  the  structure  of  the  cell,  but  they  are  all  alike 
in  that  they  get  broader  and  shorter  when  they  contract. 
The  food  that  is  most  easily  burned  in  the  muscle  is  sugar. 
Sugar  is  stored  in  the  muscle  in  the  form  of  glycogen,*  and 
when  a  nerve  impulse  comes  to  the  muscle  it  causes  the 
sugar  to  undergo  a  chemical  change.  This  chemical  change 
in  the  muscle  produces  heat  (see  Laboratory  Experiment, 
page  30)  and  the  heat  causes  such  change  in  the  muscle  cells 
that  the  cells  become  shorter  and  broader.  This  change 
is  called  the  muscular  contraction.  If  sugar  is  deficient  in 
the  muscle,  it  is  possible  for  the  cells  to  burn  fat  *  and 
protein.*  The  waste  from  this  combustion  causes  the 
fatigue*  that  is  experienced  after  muscle  work,  and  this 
waste  may  be  likened  to  the  ashes  or  clinkers  left  in  the 
furnace  after  the  coal  has  burned. 

The  duration  of  a  muscular  contraction  varies  in  different 
animals.  The  following  table  shows  the  duration  of  a  simple 
muscular  contraction : 

Insect 0.003  second 

Rabbit 0.070  second 

Frog        0.100  second 

Terrapin      . 1.000  second 

The  height  of  a  muscular  contraction  depends  upon  the 
strength  of  the  nerve  impulse  and  whether  the  muscle  is 
fresh  or  fatigued.  In  other  words  it  depends  upon- how  hard 
one  tries  and  upon  how  much  work  has  been  done.  The 


46  Healthful  Living 

strength  of  the  contraction,  however,  is  greater  after  some 
work  has  been  done.  For  this  reason,  athletes  always  warm 
up  before  trying  for  a  record  or  running  a  race  or  playing  a 
game.  It  is  greater  if  one  has  had  plenty  of  sleep  and  rest 
at  the  proper  interval,  before  the  activity.  Figure  27  shows 
how  fatigue  occurs  in  the  muscle  of  the  finger.  Using  an 


FIG.  27.  —  Tracing  of  muscular  contraction  showing  a  decrease  in 
muscular  power  (fatigue). 

ergograph,*  each  contraction  of  the  finger  is  recorded  on 
smoked  paper.  The  increase  and  decrease  in  muscular 
efficiency  is  to  be  noted. 

Alcohol  and  muscular  efficiency.  —  People  have  had  the 
erroneous  idea  that  alcohol  *  helps  the  individual  to  do  work. 
This  belief  arose  because  of  the  drug  effect  of  the  alcohol 


! 

{ 
I 

Alcohol  and  Muscle  Work 

Mountain-  Climbing 
1               ^(Abstinent  Days.                            ^%%%^j  Atcohot  Days* 

Expenditure  of  Energy  \vas  /5#  Greater  on  Alcohol  Days. 

K^^^^^^^ 

Work  Done(foot-pounds  per  second)  Averaged  16.  4%  1ess.cn  Alcohol  Days. 

I  .  J 

fcZZZZ^^ 

Time  Required  to  Climb  the  Mountain  21.  7??  Longer  on  Alcohol  Days. 

i  _  —  -i 

K/^^^^x^^^ 

y/A 

Crubrr.  "T/>e  A/c  oho/  Question  "  Va/  V2ff  No  ?  /9I2 

©,  1912,  by  Scientific  Temperance  Federation,  Boston 
FIG.  28.  —  Alcohol  decreases  the  ability  of  man  to  do  muscular  work. 


Tissues  47 

upon  the  brain.*  It  has  been  shown  that  from  8  to  10  per 
cent  less  work  is  done  when  alcohol  is  taken,  even  in  such 
small  amounts  as  that  present  in  a  pint  of  beer.  Professor 
Durig,  a  mountain  climber,  experimented  on  Mt.  Bilkencrat 
in  the  Alps  with  alcohol  to  determine  the  effect  upon  muscu- 
lar efficiency.  On  the  days  when  he  took  alcohol  amounting 
to  2  or  2-J  glasses  of  beer,  "  his  watch  showed  that  it  took 
21.7  per  cent  longer  to  reach  the  top  of  the  mountain  than 
on  the  days  when  he  took  no  alcohol  "  (Fig.  28). 

It  has  been  shown  that  alcohol  impairs  the  efficiency  of 
athletes  in  all  contests.     A  test  was  made  at  a  marathon 


A  62-Mile  Walking  Match 

Comparison  of  Abstainers  and  Non-Abstainers 

Match  held  at  Kiel,  Germany,  1908 

f-  1    Abstainers.                                                        V2Z222ZA  Non-Abstainers. 

29/5                  Percentage  of  Each  Class  Entered 

71  % 

1  VZ%%2%2^^ 

lZ%% 

60%                        Percentage  of  the  JO  Prizes  Won 

40% 

60%                               First  25  to  Reach  Goal 

40% 

27#                                Last  26  to  Reach  Goal 

73  * 

1  ^^^^^^^^^^^^^^^^^$^$$$$$$$$$$$^^x^^^$^^^$^: 

%%$ 

6%                                  Failed  to  Reach  Goal 

94% 

Akttaingra  ~on  /,t,  fnj,  3rd,  4th,  8tf>  and  fripbcey.      Drinkers  -ron  Stfi,  6th,  7tft  and  '/&//>  places. 

©,  1910,  by  Scientific  Temperance  Federation,  Boston 

FIG.  29.  —  Abstainers  are  more  effective  in  athletics.     Achievement  in 
k  all  fields  of  endeavor  is  greater  without  the  use  of  alcohol. 

race  in  Germany  with  reference  to  the  ability  of  those  who 
were  drinkers  and  those  who  were  not.  The  first  four  men 
to  cross  the  line  after  covering  a  distance  of  sixty-two  miles 
were  abstainers.  More  than  half  of  the  drinkers  fell  by  the 
way  and  only  two  of  the  abstainers  (Fig.  29).  In  baseball 
the  same  test  has  resulted  in  managers  insisting  upon  ab- 
stinence. Connie  Mack,  manager  of  the  famous  "  Athletics  " 
in  the  years  when  they  twice  won  the  championship  in  both 
leagues,  said,  "  Baseball  men  are  not  now  of  the  drinking 


48 


Healthful  Living 


FIG.  30.  —  The  general  arrangement  of  the  nervous  system  (viewed  from 
behind) .  Showing  the  brain,  the  spinal  cord,  and  the  chief  nerves  that  branch 
from  it. 


Tissues 


49 


class.  The  fact  is  that  a  big-league  player  has  to  be  in  trim 
day  in  and  day  out  or  he  is  sent  to  the  minors.  It  is  the 
survival  of  the  fittest."  He  who  would  excel  in  the  world 
must  leave  alcoholic  drink  alone. 

Nervous  tissues.  —  Knowing,  as  you  do,  how  micro- 
scopic the  cells  are  in  size,  what  would  you  think  if  you  were 
told  that  there  are  cells  in  the  body  that  have  parts  which 
extend  several  feet  in  length  !  There  are  cells  with  branches 
which  reach,  for  instance,  from  the  spinal  cord  to  the  toes 
(Fig.  30).  A  mass  of  nerve  tissue  called  the  brain  occupies 
almost  all  of  the  skull,  and  the  lower  part  of  this  nerve  tissue 
forms  the  spinal  cord,*  or  spinal  marrow.  Nerve  tissue  forms 
also  the  glistening  white  cords,  called  nerves,  going  from  the 
brain  and  spinal  cord  to  all  parts  of  the  body  (Fig.  30). 
Have  you  seen  a  hog's  brain  or  the  brain  of  an  ox  ?  However 
complicated  nerve 
tissue  may  seem 
to  be,  it  is  found 
to  consist  of  nerve 
cells  and  their 
branches,  called 
nerve  fibers. 
Some  cells, are  ar- 
ranged in  a  dis- 
tinct mass  called 
a  ganglion  (Fig. 
37). 

Nerve  structure. 
—A  nerve  consists 
of  a  great  number 
of  cell-branches  or 
nerve-fibers,  just 
as  a  number  of 
telephone  wires 
are  sometimes 
E 


4 


FIG.  31.  —  Nerve  cells  from  different  animals. 
A,  frog ;  B,  lizard  ;  C,  rat ;  D,  man  (after  Ramon  y 
Cajal). 


Sheofh  of 
connective  tissue 


50  Healthful  Living 

bound  together  in  a  cable.  Nerve  cells  grow,  become 
active  and  die,  like  other  cells,  and  like  other  cells  they 
consist  of  protoplasm  with  a  nucleus  and  nucleolus.  A 
number  of  processes  branch  off  from  them,  some  cells 
giving  off  only  one  or  two,  others  many  (Fig.  31).  One  of 
these  processes,  larger,  longer  than  the  others,  forms  the 
nerve  fiber  or  axone.  The  axis,  or  central  part  of  the  fiber, 
is  a  continuation  of  the  jelly  like  protoplasm  of  the  cell; 
this  core  is  the  essential  part  of  the  fiber.  The  axis  is  sur- 
rounded in  most  fibers  by  a  sheath  of  fatty  material  (Fig.  32) . 

This  is  for  nourish- 
ment and   protec- 

tlOD      Oi      tll6 
^    ^   jg 

FIG.  32.  —  Scheme  showing  structure  of  nerve     o-ivp«a   fn 

~,  TT  j  -j.  i  i       j.i         •          i    j.-  e  g,i  V  Co     \j\J 

fibers.     How  does  it  resemble  the  insulation  of  a     .  .     . 

copper  wire  used  in  electric  wiring?  its      characteristic 

ivory-white  ap- 
pearance. The  whole  is  strengthened  by  being  inclosed  in 
a  thin,  delicate  sheath  of  connective  tissue.  Some  of  the 
nerves  go  to  the  muscles,  and  passing  between  the  bundles 
of  fibers,  soon  divide  into  branches,  for  we  have  seen  that 
the  nerves  are  bundles  of  separate  fibers.  They  subdivide  in 
the  muscles  till  they  ultimately  send  a  single  nerve  fiber  to 
each  individual  muscle  fiber. 

How  nerves  and  muscles  work  together.  —  Suppose  you  put 
your  hand  on  a  hot  stovepipe  or  poker;  it  is  immediately 
jerked  away.  How  does  this  wonderful  thing  happen  ?  The 
heat  of  the  iron  causes  a  disturbance  in  a  nerve  fiber  ending 
just  under  the  skin  of  the  finger.  This  disturbance  travels 
rapidly  along  the  axis,  or  core,  of  the  nerve,  and  is  called  an 
impulse.*  It  is  not  a  visible  change,  but  some  influence  that 
travels  from  particle  to  particle.  It  resembles  electricity 
somewhat,  but  some  physiologists  think  it  is  like  a  wave  of 
chemical  change,  running  along  the  nerve  faster  than  a  rail- 
way train  can  run.  It  reaches  a  nerve  cell  in  the  spinal  cord. 


Tissues 


The  disturbance  there  causes  the  cell  to  send  out  impulses 
along  its  other  branches  or  fibers. 

Some  impulses  (Fig.  33)  are  sent  down  the  arm  again  to 
its  muscles,  causing  them  to  contract,  and  the  arm  is  jerked 
away,  as  we  say,  by  reflex 
action,  or  action  without 
will  on  our  part.  Other 
impulses  go  at  the  same 
time  to  the  brain,  and  we 
become  conscious  of  what 
has  happened.  The  nerves 
which  carry  impulses  to 
the  nerve  cells  (afferent) 
are  called  sensory  nerves, 
or  nerves  of  feeling,  arid 
those  which  carry  impulses 
from  the  cells  to  the  mus- 
cles (efferent)  are  called 
motor  nerves,  or  nerves 
of  motion.  Nerve  fibers 
transmit  impulses,  but  do 
not  originate  them.  An 
impulse  in  a  nerve  can  be 
excited  by  a  pinch,  a 

J    .    .  FIG.  33.  —  Reflex  arc  (after  Kolliker). 

prick,    electricity,    a    drop  The  sensory  impulse  comes  from  the  skin 

Of  acid,  a  hot  wire,  a  COld  °?d  is  directed  out  to  the  muscles  over 

7  the  motor  neurons  and  to  the  brain  by 

Object,  Or  a  thought.      Re-  the  sensory  brain  paths. 

flex  action  always  occurs 

on  account  of   some  influence   from  the  outer  world  but 

voluntary  action  comes  from  activity  in  the  brain. 

Suppose  you  step  out  of  a  warm  house  into  a  cold  wind. 
The  face  immediately  blanches  or  turns  white.  Let  us  see 
how  this  can  be  accounted  for.  There  are  muscle  fibers  in 
the  walls  of  the  blood  vessels.  The  cold  air  excites  impulses 
in  the  sensory  nerves  of  the  face,  which  travel  to  the  enlarge- 


Sensory 
/Afferent J  ncuran 


from  skfn 


52  Healthful  Living 

ment  at  the  top  of  the  spinal  cord  just  at  the  base  of  the 
brain,  called  the  medulla  oblongata  (Plate  VI).  Here  the 
impulse  reaches  a  nerve  center  which  sends  it  along  another 
set  of  nerves  that  go  to  the  muscle  fibers  in  the  walls  of  the 
blood  vessels,  causing  them  to  contract,  and  the  face  turns 
white.  Thus  we  see  how  closely  related  are  these  two  tissues. 

If  we  consider  that  the  nerves  reach  almost  everywhere  in 
the  body,  and  that  the  muscles  of  the  body  weigh  nearly  as 
much  as  all  other  tissues  together,  we  realize  how  important 
these  tissues  are.  Let  us  count  up  some  of  the  activities  in 
which  the  muscles  are  necessary :  swallowing,  digesting 
food,  breathing,  blushing,  writing,  walking,  talking,  looking, 
tasting,  chewing,  frowning,  smiling,  laughing,  circulation 
of  the  blood.  There  are  only  a  few  things,  such  as  hearing, 
smelling,  and  feeling,  that  can  sometimes  be  accomplished 
without  muscles.  In  their  functioning,  muscle  and  nerve 
cannot  be  separated.  Body  reacts  on  mind ;  mind  controls 
the  body. 

Building  good  tissues.  —  As  you  have  learned,  all  of  the 
tissues  are  built,  maintained,  and  repaired  by  living  cells. 
Life  and  health  depend  upon  the  proper  and  continuous 
activity  of  these  cells,  and  anything  that  aids  in  this  activity 
strengthens  the  body  and  prolongs  life;  anything  that  in- 
jures them  or  interferes  with  their  activity,  impairs  the 
health  and  shortens  life.  Growth  and  repair  of  tissue  are 
prompted  by  sunshine,  by  fresh  air,  by  drinking  plenty  of 
pure  water,  by  good  food,  by  active  and  happy  occupation. 
Weakness  and  injury  of  cell  and  tissue  result  from  depriving 
the  body  of  these  conditions.  When  these  essential  condi- 
tions are  absent,  the  first  step  in  the  restoration  of  health 
is  to  restore  these  conditions,  and  adapt  the  daily  life  to 
them. 

Injury  to  tissues  shortens  the  life  of  the  individual.  With 
the  knowledge  of  the  injurious  effect  of  alcohol  upon  the 
tissues  of  the  body,  life  insurance  companies  are  refusing 


Tissues  53 

insurance  to  those  who  are  drinkers.  Intelligent  persons 
would  not  sell  ten  to  fifteen  years  of  their  life  for  a  portion 
of  alcohol ;  statistics  show  that  abstainers  live  longer. 

The  effects  of  alcohol.  —  Arthur  Hunter,  of  the  New  York 
Life  Insurance  Company,  in  a  report  (May  1916)  of  the  De- 
partment of  Health  of  New  York  City,  shows  that  the  death 
rate  among  abstainers  is  from  10  to  30  per  cent  lower  than 
among  non-abstainers.  This  report  agrees  with  the  British 
statistics,  which  also  show  that  alcohol  has  an  unfavorable 
effect  on  longevity  and  that  total  abstinence  increases 
longevity.  The  Actuary  of  the  Mutual  Life  Insurance 
Company,  after  an  experience  of  fifteen  years,  came  to  the 
following  conclusion : 

"  The  difference  between  those  who  drink  beer  and  those  who 
drink  water  is  unmistakable,  while  the  loss  on  beer  drinkers  has 
been  almost  the  same  as  among  wine  and  spirit  drinkers." 

The  effect  of  drugs.  —  The  physician  uses  drugs  in  illness 
to  produce  certain  effects  in  the  body.  He  can  change  the 
rate  of  the  heart,  the  force  of  the  blood  pressure.  He  can 
stimulate  or  quiet  the  nervous  system.  He  can  increase  the 
activity  of  the  sweat  glands,  cause  changes  in  the  intestines, 
and  relax  the  muscles.  But  all  the  effects  are  accomplished 
because  of  some  condition  existing  in  a  sick  body.  The 
giving  of  medicine  must  be  preceded  by  a  diagnosis  of  the 
illness. 

There  are  some  people  who  are  so  ignorant  of  the  human 
body  that  they  are  willing  to  treat  themselves  and  even  their 
friends  with  virulent  *  drugs  and  patent  medicines.  These 
persons  frequently  recommend  a  drug  or  endorse  a  headache 
powder  because  it  relieved  a  certain  friend,  but  they  fail  to 
realize  that  every  case  of  illness  varies  in  a  marked  way,  and 
that  the  same  symptoms  *  may  be  present  for  different  dis- 
eases. 

Some  people  use  drugs  because  they  have  formed  a  habit. 


54  Healthful  Living 

Drug  habits  are  very  injurious  because  the  dose  must  con- 
stantly be  increased  to  have  the  desired  effect,  and  in  time 
the  person  becomes  dependent  on  it.  Morphin,  cocain, 
heroin,  headache  powders,  bitters,  and  tonics  are  preparations 
that  are  injurious  when  used  carelessly.  They  are  only  to 
be  used  on  prescription  by  a  physician. 

Stimulation  vs.  construction.  —  The  body  does  not  usually 
need  stimulation  from  alcohol  or  drugs.  The  stimulating 
effects  of  exercise,  wholesome  food,  fresh  air,  good  com- 
panions are  far  more  valuable.  Alcohol  must  not  be  thought 
of  as  a  stimulant,  because  it  does  not  construct  the  body 
but  it  destroys.  This  is  one  reason  why  a  person  who  has 
been  used  to  alcoholic  drinks  recovers  less  rapidly  from  an 
accident  or  surgical  operation  than  one  who  uses  none. 
Sick  benefit  societies  in  England  and  Australia  have  shown 
in  records  that  members  in  the  abstaining  societies  have 
about  half  as  much  sickness  as  those  in  the  non-abstaining 
societies. 

In  general,  it  may  be  stated  that  care  of  the  body  with 
reference  to  hygienic  living  is  the  best  kind  of  advice  to  give 
to  people  who  are  continually  ailing.  Sickness  that  re- 
quires a  physician  is  sometimes  unavoidable,  and  in  such  a 
case  care  should  be  taken  to  call  a  good  physician,  and  his 
directions  should  be  implicitly  followed.  Self-drugging  by 
the  public  is  considered  by  some  the  most  fruitful  cause  of 
disease  in  the  United  States.  "  Mind  cures  "  and  kindred 
ideas  often  do  more  by  rescuing  victims  from  poisonous  drugs 
than  through  their  calming  effect  upon  the  mind. 

APPLIED   PHYSIOLOGY 
Exercise  I 

1.  The  arteries  contain  more  of  the  yellow  fibers  of  connective 
tissue  than  the  veins.     Which  have  the  more  elastic  walls  ? 

2.  Does  fat  accumulate  in  the  body  within  the  cells  or  outside 
them? 


Tissues  55 

3.  How  can  one  "  add  a  cubit  to  his  stature  "  after  the  age  of 
twenty-five  ? 

4.  What  arguments  can  you  present  that  may  show  that  al- 
cohol causes  a  loss  in  efficiency  to  the  user? 

5.  Does  the  body  take  up  oxygen?     If  it  is  desired  to  increase 
the  process  of  oxidation  in  the  body,  how  can  this  be  accomplished? 

6.  In  what  respect  does  the  body  differ  from  a  machine  ? 

7.  Which  animal  can  contract  its  muscles  the  more  quickly, 
a  bee  or  a  frog  ? 

8.  Why  should  there  be  "  warming  up  "  exercise  in  the  gym- 
nasium before  the  main  part  of  the  gymnastic  lesson  ? 

9.  What  part  of  the  nerve  cell  is  the  nerve  fiber  ? 

10.   What  is  meant  by  the  statement  that  body  reacts  upon 
mind  and  mind  controls  body? 


LABORATORY  EXERCISES 

Experiment  1.    To  study  a  one-celled  organism  with  reference  to 
its 

(a)  structure 

(6)   reaction  to  stimuli 

(c)    properties 

Material.  —  Hay  infusion,1  pipette,  glass  slides,  cover  glasses, 
microscope,  alcohol,  and  medicine  dropper. 

Method.  —  With  the  pipette  draw  a  few  drops  of  the  scum  which 
collects  on  the  hay  infusion.  This  scum  usually  contains  a  great 
number  of  single  cell  animals,  called  paramcecia.*  Place  a  drop 
of  this  material  on  a  slide,  cover  with  a  cover  glass,  and  examine 
the  specimen  under  low  power  of  the  microscope. 

Observation.  — 

1.  What  is  the  structure  of  the  organisms  seen?     Is  there  a 
definite  shape? 

2.  Do  they  move?     Do  they  move  with  a  definite  end  for- 
ward?    Do  they  move  in  any  definite  direction? 

3.  Add  a  drop  or  two  of  alcohol  at  the  side  of  the  cover  glass. 
What  happens  to  the  movement  of  the  organism  ? 

1  Instructions  for  making  hay  infusion.  Obtain,  from  the  side  of  a  river 
or  pond,  some  grasses  that  have  grown  on  the  water's  edge.  These  dry 
grasses  will  have  on  their  stems  organisms  of  the  single  cell  type.  Place 
these  grasses  in  a  glass  jar  with  water  and  set  the  jar  in  the  window  of  the 
class  room.  In  two  or  three  days  organisms  can  easily  be  obtained. 


56  Healthful  Living 

4.  Place  a  heated  needle  at  one  side  of  the  cover  glass.     Does 
this  produce  movement  in  any  particular  direction  ? 

5.  Are  there  paramoecia  around  an  air  bubble?     What  do  they 
get  from  that?     Is  an  air  bubble  necessary  for  the  obtaining  of 
oxygen  by  this  organism? 

6.  Are  there  any  paramoecia  undergoing  division?     Reproduc- 
tion in  this  organism  occurs  when  it  is  mature  and  follows  definite 
laws  of  division.     Draw  paramoecia  showing  structure,  reaction  to 
stimuli,  and  properties. 

Experiment  2.  To  demonstrate  chemical  and  electrical  action 
with  reference  to  muscular  and  nervous  activity. 

Material.  —  Test  tube,  pieces  of  zinc,  sulphuric  acid,  zinc 
strip,  copper  strip,  current  key,  electric  bell  or  galvanometer. 

Method  and  Observation.  — 

(a)  Into  a  test  tube  place  several  pieces  of  zinc,  add  some  water 
until  the  zinc  is  covered.  Feel  the  test  tube  and  notice  any  change. 
Pour  in  sulphuric  acid.  Again  feel  the  tube  and  note  the  change. 
The  action  resulting  is  chemical  in  nature  and  heat  is  produced. 
The  energy  formed  here  in  this  chemical  action  expresses  itself  as 
heat.  The  chemical  action  in  muscle  expresses  itself  as  heat  and 
the  two  actions  are  similar. 

(6)  Make  a  voltaic  cell  by  placing  zinc  and  copper  strips  in 
a  twenty  per  cent  solution  of  sulphuric  acid.  Connect  wires  with 
the  end  of  each  strip  and  fasten  the  two  wires  by  means  of  a  key  to 
an  electric  bell  or  galvanometer.  When  the  key  is  closed  the  bell 
will  ring  or  the  needle  will  move.  The  energy  generated  here 
produces  heat,  as  can  be  determined  by  feeling  the  voltaic  cell,  but 
the  characteristic  effect  is  the  production  of  an  electric  current. 
The  chemical  action  in  the  nerve  cell  produces  a  nerve  impulse 
which  is  similar  to  an  electric  current. 


GLOSSARY 

Alcohol.  —  A  volatile,  inflammable,  colorless  liquid  of  a  penetrating 
odor  and  burning  taste.  The  chemical  formula  is  (CVHrOH). 
It  is  derived  principally  from  sugars  and  sugar-giving  sub- 
stances such  as  corn,  potatoes,  and  grapes.  Dr.  Frederick 
Peterson  classifies  it  as  a  poison  in  the  following  words,  "  Al- 
cohol is  a  poison.  It  is  claimed  by  some  that  alcohol  is  a 
food.  If  so  it  is  a  poisoned  food.  Alcohol  is  one  of  the  most 
common  causes  of  insanity,  epilepsy,  paralysis,  diseases  of  the 


Tissues  57 

liver  and  stomach,  dropsy,  and  tuberculosis."  Collier's  Weekly, 
Nov.  30,  1907. 

Appendix.  —  Vermiform  appendix  is  a  wormlike  organ  situated 
at  the  junction  of  the  small  and  large  intestine,  on  the  right 
side  of  the  abdomen.  It  is  the  seat  of  the  disease  called  by 
the  name  appendicitis. 

Axone.  —  Sometimes  spelled  axon,  and  known  as  the  axis  cylinder 
of  the  nerve  cell.  It  is  the  long  process  that  runs  from  the 
cell  body  and  joins  the  processes  of  the  nerve  cell  with  which 
it  connects. 

Brain.  —  The  organ  of  the  mind.  It  is  an  enlarged  portion  of  the 
nervous  system,  located  in  the  skull.  It  is  the  organ  of  con- 
sciousness, of  thought,  and  of  voluntary  action.  It  receives 
and  sends  impulses  and  regulates  and  controls  the  functions 
necessary  to  life. 

Carbon.  —  An  element  found  in  all  organic  substances.  It  is 
present  in  all  foods  and  usually  found  in  chemical  combina- 
tion with  hydrogen  and  oxygen. 

Combustion.  —  The  action  or  process  of  burning.  The  fire  in  the 
stove  illustrates  combustion.  In  the  human  body  combus- 
tion is  much  slower  and  the  continuous  combination  of  chemi- 
cal substances  that  produces  energy  for  work  is  similar  to  the 
combustion  in  the  steam  engine  that  produces  energy  in  the 
form  of  steam. 

Energy.  —  The  quality  by  reason  of  which  anything  is  able  to  act. 
It  represents  force.  In  physics  it  is  the  capacity  for  per- 
forming mechanical  work.  There  are  different  forms  of  energy 
and  one  form  may  be  changed  into  another.  No  energy  is 
ever  lost. 

Ergograph.  —  An  instrument  for  recording  work  done  by  the 
muscles.  Mosso,  an  Italian  physiologist,  invented  the  first 
ergograph.  The  word  comes  from  ergon,  meaning  work,  and 
graphos,  writing. 

Fat.  —  One  of  the  food  elements. 

Fatigue.  —  A  condition  of  diminished  ability  to  do  work.  The 
amount  of  fatigue  varies  under  different  conditions.  Fatigue 
of  muscle  can  be  measured  by  the  ergograph. 

Glycogen.  —  A  complex  compound  of  sugar. 

Hydrogen.  —  A  colorless,  odorless,  tasteless  gas  represented  in 
chemistry  by  the  letter  (H).  It  is  very  abundant  in  nature, 
occurring  in  combination  with  oxygen  to  form  water  (H2O) 
and  with  carbon  (C)  to  form  many  organic  compounds. 


58  Healthful  Living 

Impulse.  —  Represents  the  change  set  up  in  nerve  fibers  by 
means  of  stimuli  coming  either  from  the  endings  of  the  nerve 
in  the  cells  of  the  body  or  from  the  brain  or  spinal  cord.  The 
impulse  is  a  force  that  travels  along  the  nerve.  What  its 
nature  is  has  not  been  definitely  determined,  but  it  is  thought 
to  be  something  like  an  electric  current. 

Kinetic  energy.  —  The  energy  of  action.  It  belongs  to  every 
body  in  motion  and  is  to  be  distinguished  from  potential 
energy. 

Ligament.  —  A  band  of  firm,  compact,  fibrous  tissue  that  closely 
binds  related  parts  together.  It  is  most  often  found  binding 
the  ends  of  two  bones  together  to  form  a  joint. 

Matrix.  —  The  formative  cells  from  which  a  structure  grows. 

Mechanism.  —  The  structure  by  means  of  which  action  is  secured. 
The  neuro-muscular  mechanism  refers  to  the  arrangement 
between  the  nerves  and  muscles  by  means  of  which  certain 
types  of  action  are  secured. 

Organic.  —  Relates  to  organism  and  pertains  to  animal  and  vege- 
table life.  Also  used  to  designate  compounds.  An  organic 
compound  contains  carbon  and  is  distinguished  from  inorganic 
compounds  which  contain  metals  in  their  composition.  Some 
organic  compounds  may  contain  metal,  as  for  example,  haemo- 
globin, which  contains  iron. 

Oxidation.  —  The  process  of  uniting  of  some  chemical  substance 
with  oxygen.  All  combustion  in  the  body  is  an  example  of 
oxidation  and  the  ability  of  oxygen  to  unite  with  chemical 
compounds  and  cause  combustion  with  the  production  of 
energy  is  oxidation. 

Paramoecium.  —  A  small  animalcule  with  an  elongated,  ciliated 
body.  The  mouth  is  in  a  pit  on  the  under  surface  of  the  body. 

Periosteum.  —  The  fibro-vascular  membrane  that  covers  and 
nourishes  bone.  In  this  membrane  runs  the  blood  vessels 
which  carry  nourishment  to  the  bone. 

Potential  energy.  —  The  energy  that  is  in  the  substance  or  mechan- 
ism but  not  as  yet  in  action.  It  represents  the  energy  that  is 
available  for  action.  The  energy  in  food  is  potential  but 
when  the  food  undergoes  oxidation  and  combustion  results, 
the  energy  becomes  kinetic. 

Protein.  —  One  of  the  food  elements. 

Spinal  cord.  —  That  part  of  the  nervous  system  which  lies  within 
the  canal  formed  by  the  openings  in  the  bodies  of  the  verte- 
brae. Into  this  structure  come  the  nerves  from  all  parts  of 


Tissues  59 

the  body ;  at  the  base  of  the  skull  it  joins  with  the  brain.  The 
brain  and  spinal  cord  are  called  the  cerebro-spinal  nervous 
system. 

Symptom.  —  A  sign  or  indication  that  serves  to  point  out  the  exist- 
ence of  something  else.  Pains  in  the  body  are  symptoms  of 
a  condition  of  abnormality  in  the  body. 

Virulent.  —  Having  the  characteristic  of  strength  or  poison.  A 
virulent  infection  is  one  that  is  severe  and  dangerous  because 
the  poison  from  the  disease  is  so  strong. 


CHAPTER  IV 
ORGANS   FORMED    FROM    TISSUES 

I.  The  Different  Systems  in  the  Body. 

II.  Organs  of  the  Muscular  System. 

III.  Organs  of  the  Skeletal  System. 

IV.  Organs  of  the  Digestive  System. 
V.  Organs  of  the  Respiratory  System. 

VI.  Organs  of  the  Circulatory  System. 

VII.  Organs  of  the  Nervous  System. 

VIII.  Organs  of  the  Excretory  System. 

IX.  Organs  of  the  Reproductive  system. 


The  different  systems  in  the  body.  —  We  have  learned 
how  the  different  types  of  body  cells  were  grouped  in  tis- 
sues to  form  organs.  This  grouping  serves  the  purpose 
of  bringing  together  the  cells  of  one  kind  for  a  specific 
task  and  is  similar  to  the  collective  work  of  men  and 
women  in  an  industry.  In  the  body  we  find  muscle 
cells  arranged  in  large  masses  for  the  purpose  of  contrac- 
tion ;  in  a  similar  way  in  human  society  we  see  the  crew 
of  a  railroad  train  working  together  to  accomplish  some 
result. 

But  the  organization  of  the  body  is  more  wonderful,  even, 
than  indicated  above.  Organs  composed  of  cells  of  the 
same  or  different  variety  are  coordinated  into  systems  that 
carry  out  important  life  processes.  A  railroad  system  is  an 
organization  of  men  and  women  for  the  purpose  of  carrying- 
on  transportation.  It  includes  in  addition  to  its  executive 
and  administrative  officers,  trackmen,  clerks,  telegraphers, 

60 


Organs  Formed  from  Tissues  61 

trainmen,  repair  men.  In  similar  fashion  the  digestive 
system,  which  is  concerned  with  the  preparation  of  food  in 
the  body  for  the  use  of  the  body  includes  in  its  working 
organization  teeth,  salivary  glands,  stomach,  liver,  gall 
bladder,  pancreas,  intestine,  and  colon.  Not  all  of  the 
bodily  systems  have  so  many  different  organs  cooperating. 
The  muscular  system  is  composed  entirely  of  muscles ;  the 
nervous  system  comprises  brain,  spinal  cord,  and  nerves. 
But  whether  the  bodily  systems  are  composed  of  the  same 
kind  of  organs  or  of  many  different  organs,  they  are  all  alike 
in  that  the  organs  cooperate  in  the  system  to  accomplish  a 
specific  result.  We  recognize  in  the  body  eight  systems. 
They  are  the  muscular,  the  skeletal,  the  digestive,  the 
respiratory,  the  circulatory,  the  nervous,  the  excretory,  the 
reproductive. 

Organs  of  the  muscular  system.  —  The  organs  of  the 
muscular  system  are  the  muscles  attached  to  the  skeleton 
(Figs.  90,  91).  These  muscles  are  concerned  chiefly  in  per- 
forming movements  necessary  in  work  and  play.  We  have 
in  this  system  of  muscles  an  arrangement,  so  coordinated 
that  movement  of  the  entire  body  or  of  parts  of  the  body 
may  be  produced  readily  and  efficiently.  We  shall  learn 
later  of  some  of  the  separate  muscles  in  this  system,  but  it 
is  sufficient  at  this  time  to  classify  them  in  the  following 
groups :  Muscles  of  the  head  and  neck,  back,  chest,  ab- 
domen,* arms,  and  legs. 

There  are  other  muscles  in  the  body,  especially  in  the 
walls  of  blood  vessels  and  in  the  walls  of  hollow  organs  as 
the  stomach  and  intestine,  but  the  muscles  so  situated  are 
concerned  in  the  work  of  other  systems  and  are  not  to  be 
classified  in  the  muscular  system. 

Organs  of  the  skeletal  system.  —  The  skeletal  system 
(Fig.  43)  comprises  the  bones  of  the  skull,  vertebral  column, 
thorax,  shoulder  girdle,  pelvis,  arms,  and  legs.  These  bones 
are  assembled  in  a  definite  order  and  are  held  together  by 


62 


Healthful  Living 


ligaments.  The  bones  vary  in  shape,  size,  and  function, 
but  they. are  all  concerned  in  forming  a  framework  for  the 
structure  of  the  body. 

Organs  of  the  digestive  system   (Plate  III). — The  organs 
of  the  digestive  system  are  arranged  so  that  the  food  taken 


Salivary  G/ands 
Trachea 


GaJl_ 
B/adder 


Liver  — 


Duodenum' 


Sa/jyary 
~~G/and 


-Esophagus 


Stomach 


-Pancreas 


Vermiform_ 
Appendfx 


FIG.  34.  —  The  digestive  system. 


Organs  Formed  from  Tissues 


into  the  mouth  must  pass  along  a  certain  tract  and  receive 
the  action  of  the  secretions  of  the  organs  along  the  way. 
Study  the  diagram  in  Figure  34  and  name  the  organs.  From 
this  study  it  will  be  seen  that  the  digestive  system  is  made 
up  of  many  different  organs  and  in  this  respect  it  is  unlike 
the  muscular  or  skeletal  systems.  But  it  is  similar  in  that 
it  is  an  organization  of  organs  for  the  accomplishment  of  a 
specific  function.  The 

function  in  this  system  f      | 

is  digestion.  The  organs 
are  teeth,  tongue,  sali- 
vary glands,  esophagus,* 
stomach,*  liver,*  gall 
bladder,*  pancreas,* 
small  intestine,  large 
intestine.  After  the 
usable  parts  have  been 
taken  from  the  food,  the 
remainder  or  waste  is 
removed  from  the  body. 
This  waste  should  be 
removed  daily  and  reg- 
ularly or  the  health  will 
be  impaired. 

Organs  of  the  respira- 
tory system.  —  In  the 
case  of  the  amreba  and 
paramcecium,  which  have 
only  one  cell,  it  is  pos- 
sible for  oxygon  and 

carbon  dioxide  to  pass  directly  through  the  cell  membrane. 
In  higher  forms,  where  so  many  cells  are  situated  below  the 
surface,  a  means  must  be  provided  for  getting  oxygen  to 
the  cells  and  removing  the  carbon  dioxide.  This  is  accom- 
plished by  the  respiratory  system.  The  organs  of  this 


FIG.  35.  —  Diagram  of  respiratory 
mechanism  in  lung  showing  how  the 
blood  comes  in  contact  with  an  air  sac 
and  thus  receives  oxygen  and  gives  up 
carbon  dioxide  (modified  after  Adami  and 
Nichols) . 


64  Healthful  Living 

system  are  nose,  larynx,*  trachea,*  lungs,  and  the  muscles 
of  respiration,  the  diaphragm*  and  intercostals.*  This 
system  provides  for  getting  air  into  and  out  of  the  lungs 
but  it  is  dependent  upon  the  circulatory  system  for  convey- 
ing the  oxygen  of  the  air  from  the  lungs  to  the  cells  of  the 
body  (Fig.  35).  Study  the  structures  in  Plate  III  and  tell 
what  they  do. 

Organs  of  the  circulatory  system.  —  The  simplest  circula- 
tory system  would  be  one  in  which  there  is  a  tube  that  con- 
tracts and,  by  the  aid  of  a  valve,  forces  on  the  fluid  within 
the  tube.  The  water  supply  sj^stem  of  a  city  is  a  means  of 
water  circulation  in  which  the  pumps  at  the  station,  the 
water  mains  traversing  all  sections  of  the  city,  and  the 
running  water  are  the  essential  parts.  The  essential  organs 
of  the  circulatory  system  of  the  body  are  the  heart,  blood 
vessels,  and  blood.  In  the  city  water  system  there  are 
engineers  who  run  the  machinery  that  pumps  the  water; 
in  the  body  there  are  nerves  and  chemical  substances  that 
increase  or  decrease  the  rate  and  force  of  the  heart's  beat. 
These  controlling  agencies  are  very  important  but  they  do 
not  constitute  a  part  of  this  system.  They  illustrate  the 
harmonious  action  between  different  systems  and  one  of 
the  ways  in  which  the  nervous  system  coordinates  and 
controls  all.  Name  the  parts  in  Plates  III  and  VIII  and 
trace  the  blood  from  the  left  side  of  the  heart  until  it  reaches 
the  right  leg.  Trace  it  from  the  stomach  through  the  liver 
and  back  to  the  heart. 

Organs  of  the  nervous  system  (Plates  VI  and  VII). — 
The  simplest  nervous  system  is  one  in  which  a  stimu- 
lus is  carried  along  a  nerve  to  a  nerve  cell  and  the  response 
follows  (Fig.  36).  If  the  central  cell  or  mass  be  joined 
to  other  masses,  it  is  possible  for  a  stimulus  to  come  in 
from  one  part  and  go  out  at  another  at  a  different  level 
of  the  spinal  cord  (Fig.  37).  Suppose  that  the  first  neu- 
ral mass  enlarges  and  takes  control  over  all  the  other 


Organs  Formed  from  Tissues 


masses  and  directs   their  activities.     In  this   arrangement 
we  have  an  illustration  from  comparative  anatomy  *  of  kthe 


Nerve  Center 


Muscle  Skin 

FIG.  36.  —  Diagram  of  simple  type  of  nervous  system.     Stimulus  coming 
from  the  skin  is  sent  by  the  center  *  to  the  muscle. 

evolution*  of  the  nervous  system  from  a  simple  type  to  a 
complex  type  as  seen  in  man.     The  nervous  system  has 

_,.•'  '  "   "  "  NX      I/eod  yetny/fon 
/  \^   en/dryes  to  form 

!      /'  \      \  fhp 


FIG.  37.  —  Diagram  of  a  simple  type  of  nervous  system.  A  stimulus 
coming  in  at  A  from  the  skin  of  the  leg  may  travel  to  B  in  order  to  get 
action  by  the  muscles  of  the  arm  to  relieve  the  cause  of  the  stimulus. 

evolved  to  such  an  extent  that  in  man  it  is  composed  of 
the    brain,    spinal    cord,    cranial    nerves,*    spinal    nerves,* 


66 


Healthful  Living 


Pyramid 
Cortex 


Medulla 


FIG.  38.  —  Section*  of  the  kidney. 


ganglia,*  and  pe- 
ripheral nerves. 
The  brain  is  the 
highly  specialized 
center  which  con- 
trols and  directs 
(Fig.  37).  The 
rest  of  the  struc- 
tures exist  for  the 
purpose  of  carry- 
ing out  the  will  of 
the  brain.  Cer- 
tain acts  go  on, 
however,  without 
the  brain  control- 
ling them.  Such 
are  automatic  and  reflex.  They  represent  functions  that 
were  carried  on  before  the  brain  developed.  They  did  not 
need  the  brain  then; 
they  do  not  need  it 
now.  Such  acts  are 
breathing  and  digest- 
ing food. 

Organs  of  the  excre- 
tory system  (Plate  V). 
—  As  a  result  of  chem- 
ical changes  in  the 
body,  there  are  waste* 
substances  which  must 
be  removed.  These, 

together    with    the    ex-     FIG.  39.  — Waste  from  the  cells  going  into 

cess    of    water    in   the  blood  stream. 

blood,    are    eliminated 

by  the  chief  organs  of  the  excretory  system,  the  kidneys 

(Fig.  38).     This  system  is  very  important  in  the  mainte- 


Body 
Co// 


Body 


JJody 
Ce//. 


'y    ff/ood    Stream 


Organs  Formed  from  Tissues 


67 


nance  of  body  health,  and 
the  efficiency  with  which 
it  works  determines  very 
largely  the  health  of  the 
whole  body. 

Plate  V  shows  these 
organs  in  their  position 
in  the  body.  The  large 
arteries,  branching  off 
from  the  main  blood 
channel,  carry  the  blood 
to  the  kidneys,  and  the 
veins  carry  it  away  after 
the  waste  has  been  re- 
moved. If  the  kidneys, 
through  disease  or  other 
injury,  become  unable  to 
remove  this  waste,  the 
health  of  the  body  is 
impaired.  Figs.  39-42 
show  the  removal  of 
waste  from  the  cellular 
spaces  and  the  subse- 
quent elimination  by 
skin,  lungs,  and  kidneys. 

The  problem  of  keep- 
ing these  organs 
strong  and  well  is  a 
complex  one.  All 
the  factors  that  cause 
injury  to  the  kidney 
cells  are  not  known ; 
but  through  study, 
experiment  and 
close  observation  of 


<•>  Sweat  G/ancf 


Duct 


eat  G/and 


FIG-  40.  — Sweat  gland  of  skin  removing 
waste  from  the  blood. 


FIG.  41.  —  Waste  from  the  blood 
eliminated  by  the  lung. 


FIG.  42. —  The  elimination  of  waste  by  the 
kidney. 


68  Healthful  Living 

people's  habits  of  living,  some  important  directions  for  pre- 
serving the  efficiency  of  the  kidneys  have  been  formulated. 

It  is  generally  agreed  by  physicians  and  hygienists  that 
the  habit  of  drinking  plenty  of  pure  water  is  valuable. 
For  an  adult,  six  to  seven  glasses  a  day  are  recommended '. 
In  a  day's  schedule,  the  drinking  of  water  could  be  arranged 
in  this  way :  one  glass  on  rising,  one  at  breakfast,  one  in  the 
course  of  the  morning,  one  at  lunch,  one  in  the  middle  of  the 
afternoon,  one  at  dinner,  and  one  before  retiring. 

In  addition,  attention  is  to  be  given  to  the  prevention  of 
excessive  work  for  the  kidneys  by  reducing  the  amount  of 
waste  that  these  organs  will  have  to  eliminate.  It  will 
be  learned  later  that  the  waste  from  animal  food  is  largely 
removed  by  the  kidneys.  The  restriction  in  meat  eating 
would  seem,  therefore,  to  be  another  valuable  method  of 
protecting  these  organs. 

The  skin  is,  in  part,  an  organ  of  excretion  and  so  assists 
the  kidneys.  Keeping  the  skin  healthy  by  frequent  bathing 
and  by  wearing  proper  clothing  is  an  important  part  of 
keeping  the  kidneys  efficient.  Chilling  of  the  body,  getting 
the  feet  wet,  and  sudden  losses  in  body  heat  from  various 
other  causes,  may  be  injurious  to  the  kidneys. 

Finally,  it  should  be  noted  that  the  health  of  the  excretory 
system  cannot  be  maintained  by  patent  medicines  of  the 
Kidney  Remedy  type.  There  are  innumerable  "  cures  " 
and  "  remedies  "  advertised  in  newspapers  and  magazines 
for  the  treatment  of  kidney  disease.  They  are  worthless, 
fraudulent,  and  exceedingly  expensive.  The  restoration 
to  health  of  these  injured  organs  is  usually  a  problem  of 
adjustment  of  life,  and  the  plan  and  program  for  that 
should  be  in  the  care  of  a  skilled  physician. 

The  reproductive  system.  —  Simple  one-celled  animals, 
such  as  the  amceba,  reproduce  by  dividing  into  two  parts. 
The  entire  body  divides  and  two  new  individuals  result  from 
the  one.  In  the  higher  mammals  nature  has  formed  a 


CHARTS   OF  THE   HUMAN  BODY 

SHOWING 

DIFFERENT  SECTIONS  OF  THE  TRUNK  AND  HEAD 

AND  A  SCHEMATIC  REPRESENTATION  OF 

THE  CIRCULATION 


EXPLANATION    OF   PLATE    I 

Plate  I  shows  the  skeletal  muscles  on  the  ventral  (front)  part  of 
the  trunk.  These  muscles  lie  beneath  the  skin  and  are  attached 
to  the  bones  of  the  skeleton.  The  blood  vessels  and  nerves  which 
supply  the  muscles  come  from  within  the  body  and  send  their 
branches  into  the  fibers  of  the  muscles,  giving  nourishment  and 
stimulation,  and  controlling  elimination.  The  muscles  of  the  trunk 
are  more  important  than  the  muscles  of  the  arm  from  the  standpoint 
of  health,  because  if  the  trunk  muscles  are  not  well  developed,  the 
heart,  lungs,  digestive  organs,  and  nervous  system  will  not  be 
vigorous. 


PLATE   I 

mm. 


.OBL/OUUS; 

ABDOMNAUS 
INTERNUS-" 


EXPLANATION    OF   PLATE    II 

This  Plate  presents  the  rear  view  of  the  front  wall  of  the  body.  It 
shows  the  ribs  which  lie  beneath  the  muscles  of  the  chest  illustrated  in 
Plate  I  and  the  inner  layer  of  tissue  that  makes  up  the  structure 
of  the  abdominal  wall.  The  organs  shown  in  Plate  III  lie  against 
the  ribs  and  abdominal  wall  pictured  here. 


EXPLANATION    OF   PLATE    III 

This  Plate  shows  the  organs  of  the  trunk  as  they  appear  after 
removing  that  part  of  the  body  indicated  in  Plates  I  and  II.  The 
diaphragm  runs  transversely  across  the  body  and  separates  the 
organs  of  the  chest  (heart  and  lungs)  from  the  organs  of  the  ab- 
domen (stomach,  liver,  intestines,  etc.)-  The  diaphragm  is  a  muscle 
and  when  it  contracts  it  moves  downward  and  helps  to  bring  air 
into  the  lungs.  Notice  the  situation  of  the  liver,  and  stomach. 
Increased  action  of  the  diaphragm  following  exercise  massages  these 
organs  and  improves  their  action.  Breathing  exercises  alone  are 
not  as  valuable  as  those  that  cause  the  respirations  to  increase  in 
response  to  the  needs  of  the  body. 


PLATE   III 


EXPLANATION   OF   PLATE    IV 

This  view  shows  the  rear  of  those  structures  indicated  in  Plate  III. 
Part  of  the  lungs  have  been  removed  to  show  the  way  in  which  the 
blood  vessels  from  the  heart  enter  the  lungs,  and  to  show  the  tubes 
(bronchi)  which  carry  air  in  and  out  of  the  lungs.  In  the  abdominal 
part  there  are  two  organs  that  were  not  shown  in  Plate  III.  One  is 
the  pancreas,  that  lies  behind  the  stomach,  and  the  other  is  the  gall 
bladder,  that  lies  on  the  under  surface  of  the  liver.  Notice  the  large 
blood  vessels  going  to  the  intestines.  If  the  muscular  wall  shown 
in  Plate  I  is  not  held  in  place  and  well  contracted  these  blood  vessels 
will  be  stretched  and  will  be  less  able  to  carry  blood  to  the  organs 
of  the  abdomen.  It  is  important,  therefore,  always  to  stand  erect 
so  that  the  organs  of  the  abdomen  will  receive  the  full  supply  of 
blood  which  they  need. 


PLATE   IV 


EXPLANATION   OF   PLATE   V 

This  Plate  presents  the  front  view  of  the  back  wall  of  the  trunk 
with  all  the  organs  of  the  chest  and  abdomen  removed  except  the 
kidneys  and  bladder.  This  view  shows  the  esophagus,  which  empties 
into  the  stomach ;  the  large  blood  vessels  going  to  and  from  the 
heart.  The  kidneys  are  seen  receiving  blood  from  the  renal  artery 
and  sending  blood  away  in  the  renal  vein.  The  kidneys  take  the 
impurities  from  the  blood  and  remove  the  excess  of  water.  The 
excretion  is  carried  in  tubes,  marked  ureter,  to  the  bladder.  All 
the  organs  are  of  importance  in  maintaining  the  health  and  strength 
of  the  body,  and  the  excretory  system  is  as  important  as  if  not  more 
important  than  the  others. 


PLATE   V 


EXPLANATION    OF   PLATE   VI 

This  Plate  shows  structures  inside  the  skull  and  face.  It  is  a 
composite  picture,  being  made  up  of  several  different  sections.  It 
shows  the  spinal  cord  with  its  connections  with  the  cerebrum  (brain) ; 
the  eye  and  optic  nerve ;  and  nerves  going  from  the  brain  to  the 
teeth,  the  nose,  and  the  muscles  of  the  neck.  It  is  to  be  noticed  that 
the  brain  and  nerves  are  well  protected,  the  brain  being  covered  by 
the  bony  skull  and  the  nerves  gaining  protection  from  the  bones  of 
the  face  and  soft  parts.  The  bones  protecting  the  spinal  cord  have 
been  cut  away  in  order  to  show  this  structure. 


PLATE  VI 


PLATE   VII 


^-ai-CKL^ 


EXPLANATION   OF   PLATE   VII 

This  view  of  the  head  is  that  which  would  be  presented  by 
looking  at  the  surface  of  the  sagittal  section  through  the  head. 
The  opening  from  the  mouth  into  the  esophagus  and  the  path- 
way from  the  nose  to  the  lungs  are  shown.  The  spinal  cord 
entering  the  base  of  the  brain  is  clearly  indicated  and  some  of  the 
internal  structures  of  the  brain  are  represented.  The  corpus  callo- 
sum  is  composed  of  fibers  connecting  the  two  sides  of  the  brain. 
The  cerebellum  is  shown  cut  across ;  the  pons  lies  in  front  of  it. 
In  the  medulla  are  situated  the  vital  centers  of  life  —  the  respiratory, 
cardiac,  and  vaso-motor  centers. 


EXPLANATION    OF   PLATE   VIII 

[OVER] 

This  Plate  represents  the  circulation  of  the  blood.  The  blood 
flowing  from  the  left  side  of  the  heart  is  represented  in  the  arteries 
by  a  circular  marking ;  that  coming  to  the  right  side  of  the  heart 
and  from  there  to  the  lungs,  in  the  veins  by  a  straight  line.  This 
representation  of  veins  and  arteries  indicates  a  difference  in  structure  ; 
it  also  suggests  one  very  important  fact  in  the  circulation  —  the 
blood  which  the  heart  sends  out  to  the  cells  of  the  body  is  not  the 
same  in  composition  as  that  which  returns  to  the  heart.  The  chief 
difference  is  a  waste  product  of  oxidation,  carbon  dioxide.  Trace 
the  blood  from  the  left  side  of  the  heart  to  the  head,  hands,  and 
feet  by  the  arteries;  trace  the  blood  from  the  right  side  of  the 
heart  to  the  lungs ;  and  trace  the  blood  from  the  head,  hands,  and 
feet  by  the  veins  to  the  heart. 


PLATE  VIII 


Organs  Formed  from  Tissues  69 

complex  system  of  special  organs  to  care  for  this  important 
work  Of  reproducing  the  species.  Nature's  laws  here  as 
elsewhere  are  helpful  when  understood.  Ignorance  of  these 
laws  results,  frequently,  in  disease,  in  loss  of  health  and 
happiness.  Parents  or  the  family  physician  are  the  logical 
persons  to  instruct  children  in  these  laws.  It  should  be 
remembered  that  the  proper  care  and  functioning  of  this 
system  determines  not  only  the  health  and  happiness  of  the 
individual,  but  also  the  health  and  prosperity  of  the  race. 

APPLIED   ANATOMY 
LABORATORY   EXERCISES 

1.  To  demonstrate  the  digestive  organs. 

Obtain  from  the  body  of  a  cat  or  rabbit  the  stomach  and  in- 
testines. Tie  off  the  two  ends.  Show  the  relations  between 
stomach  and  intestines.  Indicate  the  mesentery  and  show  how 
the  blood  vessels  coming  to  the  intestines  run  in  the  mesentery 
supporting  the  tube. 

2.  To  demonstrate  the  organs  of  respiration  and  circulation. 
From  the  same  source  as  in   (1)  obtain  the  lungs  and    heart. 

Place  the  specimen  in  water.  Do  the  lungs  float  ?  Show  the  rela- 
tion between  lungs  and  heart. 

3.  To  demonstrate  organs  of  the  nervous  system. 

Obtain  from  the  butcher  a  fresh  calf  brain  and  also  a  section  of 
the  spinal  cord  of  the  hog  or  calf.  Show  how  the  spinal  nerves  come 
off  from  the  cord  and  indicate  the  root  of  origin  of  the  cranial  nerves. 

4.  To  demonstrate  organs  of  the  muscular  system. 

Obtain  from  the  butcher  the  fore  leg  of  a  can3.  Dissect  out  the 
tendinous  attachment  of  the  muscles  and  at  the  joint  indicate  the 
difference  between  the  tendon  and  the  ligament. 

5.  To  demonstrate  the  organs  of  the  excretory  system. 
Obtain  from  the  butcher  the  kidneys  from  a  calf  and  indicate 

for  the  class  the  arterial  and  venous  blood  supply.  By  a  diagram 
show  how  the  kidney  removes  waste  from  the  body  and  emphasize 
the  importance  of  water  in  the  diet. 

GLOSSARY 

Abdomen.  —  The  cavity  lying  between  the  diaphragm  and  pelvis 
and  holding  the  viscera.     The  viscera  is  the  plural  term  for 


yo  Healthful  Living 

viscus.  Viscus  refers  to  the  organs  in  the  abdomen,  such  as 
the  intestines  and  stomach. 

Center.  —  Used  here  in  connection  with  the  nervous  system,  i.e., 
nerve  center.  A  group  of  nerve  cells  arranged  in  a  circum- 
scribed mass  for  the  purpose  of  carrying  on  a  particular  func- 
tion or  coordination. 

Cerebrum.  —  The  upper  and  foremost  part  of  the  brain.  It  con- 
sists of  two  symmetrical  halves,  called  hemispheres.  In  man 
and  the  higher  animals  the  cerebrum  is  the  chief  bulk  of  the 
brain.  It  is  supposed  to  be  the  seat  of  thought  and  will. 

Cerebellum.  —  A  part  of  the  brain  lying  below  and  behind  the 
cerebrum.  It  is  much  smaller  than  the  cerebrum  and  is  con- 
cerned with  equilibrium  and  allied  functions. 

Comparative  anatomy.  —  The  study  of  the  structure  of  different 
animals  and  man  with  reference  to  similarities  and  differences 
in  structure  and  development  of  organs  in  different  species. 

Corpus  callosum.  —  A  great  band  of  nerve  fibers  that  runs  trans- 
versely across  the  brain,  connecting  the  two  hemispheres.  As 
compared  with  other  parts  of  the  brain,  this  band  is  very  hard 
and  it  receives  its  name  from  being  a  "  hard  body." 

Cranial  nerves.  —  The  nerves  that  come  off  from  the  brain.  There 
are  twelve  pairs  and  comprise  such  nerves  as  the  optic  (to  the 
eyes),  the  auditory  (to  the  ears),  the  facial  (to  the  face),  and 
the  vagus  (to  the  heart). 

Diaphragm.  —  A  muscle  situated  between  the  cavity  of  the  chest 
and  the  abdomen.  It  is  the  chief  muscle  pf,  respiration. 
When  it  contracts  it  descends  and  causes  air  to  rush  into  the 
lungs ;  when  it  relaxes  it  rises  and  forces  the  air  out. 

Esophagus.  —  A  tube  composed  of  muscle  and  membrane,  about 
ten  inches  long.  It  serves  to  carry  food  and  drink  from  the 
mouth  to  the  stomach.  It  is  sometimes  called  the  gullet. 

Evolution.  —  A  term  to  denote  the  development  of  the  complex 
individual  from  the  single  cell  and  to  explain  the  way  in  which 
all  development  has  occurred  and  the  conditions  modifying 
such  development. 

Gall  bladder.  —  A  muscular  bag  that  lies  on  the  under  surface  of 
the  liver  and  holds  the  bile  secreted  by  that  organ. 

Ganglion.  —  A  group  of  nerve  cells  lying  outside  the  spinal  cord. 

Intercostal.  —  One  of  a  group  of  muscles  attached  between  the  ribs 
and  concerned  in  respiration. 

Larynx.  —  The  upper  part  of  the  air  tube.  It  contains  the  vocal 
cords. 


Organs  Formed  from  Tissues  71 

Liver.  —  A  large  gland  composed  mainly  of  epithelium,  situated 
in  the  upper  part  of  the  abdomen  on  the  right  side.  It  se- 
cretes a  liquid  called  bile ;  it  stores  sugar  in  the  form  of  gly- 
cogen ;  and  it  removes  certain  waste  substances  that  come  to 
it  in  the  blood. 

Medulla  oblongata.  —  The  extreme  upper  part  of  the  spinal  cord, 
forming  the  connecting  structure  between  the  cord  and  the 
brain.  It  is  conelike,  and  about  one  inch  long.  It  contains 
important  nerve  centers  such  as  the  respiratory  center,  the 
cardiac  center,  the  vaso-motor  center,  etc. 

Pancreas.  —  An  organ  of  digestion  concerned  in  the  metabolism  of 
fat,  sugar,  and  protein. 

Pons.  —  Usually  called  the  Pons  Varolii  after  the  anatomist  of 
Bologna,  Constanza  Varoli.  It  is  a  part  which  contains  the 
fibers  from  the  two  hemispheres  of  the  cerebellum.  The 
corpus  callosum  was  the  connection  between  the  two  parts 
of  the  cerebrum ;  the  pons  is  the  connection  between  the 
two  parts  of  the  cerebellum. 

Section.  —  A  picture  or  view  of  a  part  or  body  that  would  be  seen  if 
it  were  cut  by  an  intersecting  plane.  If  the  cut  is  made  across, 
the  section  is  transverse;  if  lengthwise,  it  is  called  a  longi- 
tudinal section. 

Spinal  nerves.  —  Nerves  that  have  an  attachment  with  the  spinal 
cord.  They  comprise  nerves  going  to  the  cord  and  nerves 
coming  away  from  the  cord. 

Stomach.  —  An  enlargement  of  the  alimentary  tract  that  serves  to 
hold  food  while  it  is  being  acted  upon  by  digestive  juices  se- 
creted by  the  stomach. 

Trachea.  —  The  tube  connecting  the  lungs  with  the  mouth  and  nose 
cavities. 

Vaso-motor.  —  Refers  to  movement  produced  in  the  blood  vessels. 
This  movement  may  be  constriction  in  which  the  lumen  grows 
smaller ;  or  it  may  be  dilatation  in  which  the  lumen  grows 
larger.  Vaso  comes  from  vas,  meaning  vessel.  Constriction  of 
the  vessel  is  called  vaso-constriction ;  dilatation  of  the  vessel 
is  called  vaso-dilatation. 

Waste.  —  The  waste  substances  in  the  body  result  from  the  chem- 
ical changes  that  go  on  in  the  production  of  energy.  Ashes 
represent  the  waste  of  combustion  when  wood  and  coal  are 
burned.  The  waste  of  the  cells  of  the  body  is  represented  by 
such  substances  as  carbon  dioxide,  urea,  uric  acid,  creatin, 
xanthin,  etc. 


CHAPTER  V 
THE    SKELETON    FRAMEWORK    OF    THE    BODY 

I.    The  Use  of  the  Skeleton. 

For  attachment  of  muscles 
For  support  and  protection 
For  movement 
II.   Parts  of  the  Skeleton. 
The  skull 

The  vertebral  column 
The  thorax 
The  shoulder  girdle 
The  arm 
The  leg 

III.  The  Structure  of  a  Long  Bone. 

IV.  The  Composition  of  Bone. 
V.   Joints. 

Motion  in  movable  joints 


The  use  of  the  skeleton.  —  There  are  some  animals,  such 
as  the  slug  and  the  jelly  fish,  that  do  not  possess  any  hard 
part  corresponding  to  a  skeleton.  Such  an  animal  if  it  lives 
on  land,  lies  flat  on  the  ground,  and  moves  slowly  and  with 
difficulty.  Animal  life  in  its  lowest  forms  is  characterized 
by  a  resemblance  to  plants ;  in  fact,  in  the  case  of  bacteria* 
it  is  not  known  whether  they  are  plants  or  animals.  Plants 
in  both  high  and  low  forms  are  characterized  by  their  im- 
mobility. Animals  in  their  evolution  from  lower  to  higher 
forms  have  increased  their  power  to  move  about.  So  far 
as  movement  on  land  is  concerned,  the  feature  that  brought 
an  increased  range  of  movement  was  the  bony  skeleton. 

72 


The  Skeleton  Framework  of  the  Body  73 

Evolution  is  a  slow  and  gradual  process  and  the  skeleton  of 
man  is  the  result  of  centuries  of  development. 

For  attachment  of  muscles.  —  The  bones  that  form  the 
skeleton  of  man  (Fig.  43)  make  possible  not  only  movement 
of  the  body  itself  but  also  of  its  parts.  Muscles  attached 
to  two  bones,  on  contracting  and  shortening,  pull  the  two 
bones  toward  each  other.  If  the  bone  at  one  attachment  is 
held  in  a  rigid  way,  the  contraction  will  result  in  a  move- 
ment of  the  other  bone  toward  the  fixed  part.  We  say, 
therefore,  that  bones  serve  for  the  attachment  of  muscles 
and  give  support  from  which  the  muscles  can  pull. 

For  support  and  protection.  —  Bones  also  give  support  to 
the  body.  Man  could  not  be  an  erect  animal  if  there  were 
not  a  rigid  skeleton  to  support  his  organs"  and  parts.  In 
addition,  the  bones  serve  for  protection,  for  even  in  man, 
so  capable  of  self-protection,  it  is  necessary  to  have  the  skele- 
ton to  protect  some  of  the  delicate  organs.  Some  animals 
have  developed  for  protection  other  means  also.  The  scales 
of  the  fish,  the  quills  of  the  porcupine,  the  heavy  fur  of  arctic 
animals,  serve  to  protect  these  animals  from  various  forces  in 
their  separate  environment.* 

In  man  the  bones  that  protect  the  vital  organs  are  flat, 
as  the  breastbone  and  shoulder  blade,  the  ribs,  which  pro- 
tect the  heart  and  lungs,  and  the  skull  bones,  which  protect 
the  soft  and  delicate  brain. 

For  movement.  —  Bones  serve  for  the  attachment  of 
muscles,  they  give  support  and  protection,  and  they  in- 
crease the  possibilities  of  movement  of  the  parts  of  the  body. 
The  muscles  by  their  shortening  accomplish  very  simple 
and  imperfect  motions ;  by  using  the  bones  for  support  and 
as  levers,  this  motion  is  changed  in  rate,  direction,  and  place 
of  application. 

The  long  bones  of  the  arms  and  legs,  with  the  fingers  and 
toes,  have  motion  as  their  chief  function.  The  ribs  are  flat  but 
they  are  the  longest  bones  in  the  body  in  proportion  to  their 


74 


Healthful  Living 


Cranium. 


(Clavic/eJ  Co/Jar  Son  e. 


(Scapula]. 
Shoutc/er  Blade 

tfumerus. 


Pe/vic  £one 
Cav/'fy  of  Pelvis 


Pate/la  ftfnee  C0pJ 


Tarsa/s 


'asa/Bones. 

Ma/arfCheekjBone. 
Superior  Maxil/ary  Bones. 
Inferior  Maxillary  Hone. 
Spinal  Column  Cervical  Region. 


fSternurnJSreastSone. 


Ribs. 


Spinal  Column 


•Radius. 
Ulna. 


tatersals 
-Phalanges 


FIG.  43.  —  The  skeleton. 


•  The  Skeleton  Framework  of  the  Body  75 

size,  and  enable  us  to  perform  the  important  motions  of 
breathing.  Yet  they  are  classed  as  flat  bones,  for  they  lack 
the  round  shaft  and  enlarged  ends  or  heads  which  typical 
long  bones  have.  Even  the  bones  of  the  instep,  palm, 
fingers,  and  toes,  which  are  the  smallest  of  the  long  bones, 
have  the  shaft  and  heads. 

Many  of  the  small,  short  bones  are  stronger  than  the  long, 
slender  bones,  or  the  flat,  thin  ones.  These  bones  are  called 
irregular  bones.  They  are  not  easily  broken  and  their  chief 
function  is  support.  They  are  found  in  the  spine,  the 
ankle,  the  wrist,  the  knee,  and  the  face.  We  should  re- 
member that  the  irregular  bones  also  assist  in  the  two  other 
functions  of  protection  and  motion  ;  also  that  the  long  bones 
and  the  flat  bones  are  not  confined  to  one  function  but  par- 
ticipate in  all  three  functions  (Fig.  43). 

Parts  of  the  skeleton.  —  The  central  part  of  the  skeleton 
called  the  vertebral  or  spinal  column,  forms  a  firm  but 
flexible  axis.  The  head  rests  upon  the  top  of  this  column. 
The  ribs  are  attached  at  its  side  to  make  the  walls  of  the 
chest.  The  shoulder  girdle  rests  upon  the  chest,  and  the 
hip  girdle  is  attached  to  the  base  of  the  spinal  column.  These 
girdles  connect  the  upper  and  lower  limbs  with  the  trunk. 
The  bones  of  the  head  and  trunk  form  the  axial  skeleton. 
The  bones  of  the  girdles  and  limbs  are  called  the  appended 
skeleton,  since  they  are  appended  to  the  axial  framework. 

The  skull  (Fig.  44).  —  The  skull  is  the  cranium,  or  casket 
which  contains  the  brain,  and  the  facial  bones.  The  arched 
form  of  the  skull  is  the  best  shape  for  resisting  blows  and 
pressure.  Its  bones  are  so  firm  and  hard  that  bullets  some- 
times glance  from  it,  but  the  structures  within  the  skull  are 
so  important  and  delicate  that  in  war  the  head  is  protected 
by  a  metal  helmet  to  resist  shrapnel.  The  occipital  bone 
curves  under  at  the  back  of  the  neck  to  aid  in  forming  the 
floor  of  the  skull.  It  has  two  projections  called  condyles* 
(knuckles)  situated  just  behind  its  junction  with  the  sphenoid 


76 


Healthful  Living 


HyoidJBone 


(wedgelike)  bone.  The  condyles  fit  into  depressions  (Fig.  45) 
in  the  uppermost  vertebra;  thus  the  head  rests  and  rocks 

upon  the  spinal 
column.  Grasp 
the  neck  with 
both  hands  so  as 
to  hold  it  motion- 
less and  stiff,  and 
find  whether  the 
head  rocks  for- 
ward and  back- 
ward, or  side  wise. 
Between  the  con- 
dyles is  a  large 
opening  through 
which  the  spinal 
cord  goes  from  the 

FIG.  44.  —  Side  view  of  skull.     The  larger  bones  brain, 
are  named  in  the  figure.     The  lower  jaw  is  dropped          jr^g  verteoraZ  col- 
down.     Its  socket  in  the  skull  is  shown  in  front  of 

the  opening  of  the  ear,  a;    b,  process  of  temporal  Utnn. — The  Spinal 

passing  to  malar,  or  cheek  bone.     Locate  one  of  column        consists 

in  the  adult  of 
twenty-six  bones 
(Fig. 45).  Twenty- 
four  of  these  bones 
have  a  similar 
shape,  and  each  is 
called  a  vertebra 
(Latin,  that  which 
turns) .  The  other 

two  have  the  names  of  sacrum  and  coccyx.  The  first  seven 
vertebrae  are  in  the  neck  and  are  called  cervical  (of  the  neck) . 
The  next  twelve  are  those  to  which  the  ribs  are  attached 
and  are  called  thoracic  or  dorsal  (of  the  back).  The  next 
five  vertebrae  are  in  the  loins  or  lumbar  region  and  are 


the  condyles  or  projections  which  rest  in  sockets 
on  the  highest  vertebra;  the  hyoid  bone,  not  joined 
to  any  other  bone,  except  by  muscles ;  opening  of 
ear  and  styloid  process.  A  small  part  of  the 
sphenoid  bone  is  shown ;  the  main  part  is  at  base 
of  skull.  The  eight  cranial  bones  are  : 

One  Frontal  (forehead) 
One  Occipital  (back  and  floor) 
Two  Parietal  (sides  and  roof) 
One  Sphenoid  (central  floor) 
Two  Temporal  (sides) 
One  Ethmoid  (front  floor) 


The  Skeleton  Framework  of  the  Body 


77 


called  lumbar  (of  the  loins).  They 
are  the  largest  of  the  vertebrae. 
The  lowest  lumbar  vertebra  rests 
upon  the  sacrum  (sacred,  because 
this  bone  of  lower  animals  was 
once  used  in  sacrifice).  In  infancy 
the  sacrum  consists  of  five  ver- 
tebrae ;  these  begin  uniting  at  two 
years  of  age  and  complete  the 
union  at  twenty  years.  The 
coccyx  (cuckoo,  from  its  resem- 
blance to  the  bill  of  a  cuckoo),  or 
last  bone  of  the  column,  is  that 
part  of  the  skeleton  which  in  the 
lower  animals  forms  the  tail.  In 
infancy  it  consists  of  four  small 
bones  which  later  unite  into  one. 
The  coccyx  is  of  little  use,  -but  the 
sacrum  is  a  highly  important  bone, 
since  to  its  sides  are  attached  the 
bones  of  the  pelvic  arch,  by  which 
the  weight  of  the  body  is  trans- 
mitted to  the  legs. 

Vertebrae.  —  The  different  ver- 
tebrae all  conform  to  a  general  plan 
of  structure.  On  examination  they 
show  a  large  massive  central  part 
(the  body),  and  leading  from  this 
part  and  running  posteriorly  (back- 
ward) are  two  processes  of  bone, 
the  pedicles  (Fig.  46,  A).  The 
pedicles  are  continuous  with  two 
other  parts,  the  laminae,  and  with 
them  form  the  neural  arch.  Where 
pedicles  and  laminae  join  there  runs 


..J 


FIG.  45.  —  Spinal  column 
(seen  from  behind) .  s,  spinous 
process ;  t,  transverse  process. 
Find  the  7  cervical,  12  tho- 
racic, 5  lumbar  vertebrae.  Do 
the  sacrum  and  coccyx  show 
evidence  of  having  been  di- 
vided in  early  growth  ? 


Healthful  Living 


off  horizontally  to  each  side  a  process,  the  transverse  pro- 
cess. The  laminae  at  their  junction  behind  meet  the  spinal 
process,  which  points  directly  backward. 


Neuro/  CanaJ 


-So/nous  Process 

•Lom/na 
Transverse  f roc  ess 


Opening  for  J?x>l 
of  Sprna/  Ner  ve 

Spinovs 
Process 


FIG.  46.  —  A,  plan  of  a  typical  vertebra  showing  rib  attachment;  B, 
side  view  of  several  vertebrae  showing  inter-vertebral  fibre-cartilage  and 
openings  for  spinal  nerves. 

The  arches  formed  by  the  pedicles  and  laminae  serve 
admirably  for  protection  to  the  highly  specialized  spinal 
cord  (part  of  the  nervous  system).  The  processes  are  well 
adapted  by  their  roughened  surfaces  for  the  attachment  of 
muscles  and  ligaments.  Strictly  speaking,  however,  the 
rough  places  on  the  bones  are  caused  by  the  pull  exerted  by 


The  Skeleton  Framework  of  the  Body 


79 


the  muscles  at  the  point  of  attachment.  Between  the 
bodies  of  the  vertebrae  are  elastic  cushions  (Fig.  46,  R) 
called  fibro-car- 
tilages. 
pads  are 


These 
of  im- 
portance in  pre- 
venting jar  to  the 
spine,  arid  they 
assist  greatly  in 
all  movements  of 
the  spine.  It  will 
be  seen, therefore, 
that  the  spine 
is  constructed  to 
support  the  head, 
to  keep  the  trunk 
erect,  to  protect 
the  spinal  cord  of 
the  nervous  sys- 
tem (Fig.  47) ,  and 
to  allow  motion  of 
the  spine.  This 
last  function  is 
provided  for  by 
the  separate  ver- 
tebrae,  which 
means,  of  course, 
that  each  verte- 
bra need  move 
only  a  little  to 
get  a  resulting 
large  movement. 
The  whole  is 
equal  to  the  sum 
of  its  parts. 


/Verves  to  Neck. 


Nerves  to  Lower 
A  bdorxen  and 


Sciatic  Nerve  (o  Leg. 


FIG.  47.  —  Spinal  cord  in  the  vertebral  column, 
showing  segments  of  cord  and  emergence  of  nerves 
going  to  arms,  trunk,  and  legs.  (After  Dejerine 
and  Thomas  in  Starr.) 


8o 


Healthful  Living 


••CfRV/OAL    CURVE 
Arc  of  18  degrees 
Radius  of  Arc  6%  in 


THORAC/C- 


Arc  of  42  degrees 
Radius  of  Arc  12  %/ 


Curves  of  the  Spine.  —  When  the  vertebral  column  is 
viewed  from  the  side  (Fig.  47),  it  shows  four  curves.     The 

cervical  curve  starts 
with  the  first  verte- 
bra and  extends  to 
the  second  thoracic 
vertebra.  It  is  con- 
vex forward.  The 
thoracic  curve  be- 
gins with  the  second 
thoracic  and  ends 
with  the  twelfth  tho- 
racic. This  curve  is 
concave  forward. 
The  lumbar  curve 
begins  with  the 
twelfth  thoracic  and 
ends  at  the  junction 
of  sacrum  and  fifth 
dorsal.  It  is  convex 
forward.  The  sacral 
curve  completes  the 
picture  with  a  deep 
concavity  forward. 
Figure  48  represents 
the  curvature  in  these 
sections.  The  degree 
represents  the  num- 
ber of  degrees  in  a 
segment  of  a  circle 
of  which  this  curve 

*S       tne      arc< 


-LUMBAR  CUffVf 

Arc  of  8O  degrees 
Radius  of  Arc  5%in. 


SACRAL 

Arc  ofJ25  degrees 
Radius  of  Arc  2% in. 


FIG.    48.  —  Normal    curves    of    the    spine.  m 

Notice  that  the  spine  is  faced  in  the  opposite  figures  given  in  inches 
direction    from   the   one   shown    in    Fig.   47.  Ai  j« 

These  curves  are  normal.     They  should   not  ^Present    the   radlUS 

be  changed  because  the  body  is  injured.  of  each  segment. 


The  Skeleton  Framework  of  the  Body 


81 


The  thoracic  and  sacral  curves  are  called  primary  curves 
because  they  are  present  when  the  child  is  born.  The 
cervical  and  lumbar  curves  are  compensatory  or  secondary, 
because  they  develop  after  birth  by  the  effort  the  child 
makes  to  hold  up  its  head  and  to  walk  erect.  Now,  the  im- 
portant thing  for  us  to  remember  is  that  nature  provides  us 
with  a  backbone  that  has  curves.  These  curves  are  normal 
and  they  should  be  maintained.  Some  boys  and  girls  stoop 
over  so  much  that  they  increase  the  thoracic  curve.  This 
destroys  their  good  appearance  and  also  interferes  with 
the  development 
of  their  lungs. 
Girls  by  improper 
modes  of  dressing 
often  increase  the 
lumbar  curve  too 
much.  This  re- 
sults in  a  weak 
and  painful  back. 

The     thorax.  - 
The     thorax,     or 
chest,    is    formed 
in  the  rear  by  the 
twelve       thoracic 
vertebrae;  in  front, 
somewhat  parallel 
to  the  spinal  col- 
umn, but  approaching  it  above,  is  the  sternum,  or  breast- 
bone (Fig.  49). 

Twelve  ribs  curve  around  each  side.  Each  rib  joins  one 
of  the  thoracic  vertebrae  behind.  The  first  seven  pairs 
directly  join  the  sternum  in  front  by  means  of  short  carti- 
lages, and  are  called  true  ribs.  The  next  three  pairs,  called 
false  ribs,  do  not  reach  the  sternum,  but  each  rib  unites  to 
the  rib  above  by  a  long  cartilage.  The  last  two  pairs  are 


FIG.  49.  —  Front  view  of  thorax  and  shoulder 
girdle  showing  projection  of  heart  on  chest  wall. 


82 


Healthful  Living 


called  floating  ribs,  since  the  front  ends  are  not  attached 
to  a  bone  either  directly,  like  the  true  ribs,  or  indirectly,  like 
the  false  ribs,  but  rest  in  the  mus- 
cular walls  of  the  waist  (Fig.  50). 

The  shoulder  girdle.  —  The  arms 
are  attached  to  the  trunk  by  the 
shoulder  girdle.  This  consists  of 
four  bones,  two  on  each  side,  scapulae 
or  shoulder  blades,  and  the  clavicles, 
or  collar  bones.  Each  shoulder  is 
composed  of  a  clavicle  (key,  from  its 
resemblance  to  the  ancient  key)  and 
a  scapula  (Fig.  51).  The  scapula 
(trowel)  occupies  the  rear  part  of  the 
shoulder.  It  is  a  large  flat  bone  of 
triangular  shape  and  bears  in  the 
end  at  the  angle  of  the  shoulder  a 
shallow  socket  into  which  is  fitted 
the  end  of  the  upper  bone  of  the  arm. 
The  clavicle  is  a  slender  bone,  round 
and  slightly  curved,  which  occupies 
the  front  of  the  shoulder,  and  is 
joined  at  one  end  to  the  scapula  arid 
at  the  other  to  the  sternum.  The 
clavicles  can  be  felt  at  the  right  and 
left  of  the  base  of  the  neck. 

The  arm.  —  The  arm  consists  of  the  upper  arm,  forearm, 
wrist,  and  hand  (Fig.  51).  The  upper  arm  extends  to  the 
elbow  and  has  only  one  bone,  the  humerus.  From  the 
elbow  to  the  wrist  is  the  forearm,  formed  of  two  bones, 
arranged  parallel  to  each  other ;  the  ulna  is  on  the  inner  side, 
the  side  corresponding  to  the  little  finger ;  the  radius  oc- 
cupies the  outer  side,  the  same  side  as  the  thumb.  At  the 
lower  end  of  each,  a  bump  may  be  felt,  the  bump  on  the 
ulna  being  larger.  The  wrist  is  called  the  carpus,*  and  is 


FIG.  50.  —  Side  view  of 
thorax,  spine,  and  pelvis. 


The  Skeleton  Framework  of  the  Body  83 

composed  of  eight  small  bones  arranged  parallel  in  two  rows, 
four  in  each  row,  running  across  the  wrist.     Next  follows 


--  Scapula 


Femur 


Humerus 


Patella 


Utna 11  \—  Radius 


—Fibula 


TUbfa 


Carp&fs—--- 
Afetacarpals  — 


•-•Phalanges 

FIG.  51.  —  The  arm  and 
the  shoulder.  Seen  from 
the  rear.  Why  do  the 
fingers  seem  so  long? 


Tarsals 

Metatarsafs--; 


-Phalongt 


FIG.  52.  —  Bones  of  the 
hip  and  leg.     Front  view. 


the  metacarpus*  (beyond  the  carpus)  (Fig.  51),  or  the  bones 
in  the  palm  of  the  hand.  The  palm  is  composed  of  five 
long  bones,  each  serving  to  support  a  finger  or  thumb.  Each 


84  Healthful  Living 

finger  is  composed  of  three  small  bones  called  phalanges 
(rows  of  soldiers) ;  the  thumb  has  only  two.  The  thumb  is 
more  movable  than  the  fingers,  and  can  be  opposed  to  each 
of  them. 

The  leg.  —  The  skeleton  of  a  lower  limb  has  a  striking 
resemblance  to  that  of  an  upper  limb  (Fig.  52).     The  hip 

Fifth  Lumbar  Vertebra- 


-Sacrum 

A  cetabulum  • 

\H\M\\\  :N>V.X     '^W  UKon-amcr         /  MWfVf/amammtmri 

Coccyx 


FIG.  53.  —  The  pelvis. 

girdle,  corresponding  to  the  shoulder  girdle,  forms  the  hip. 
The  hip  bones,  or  innominate  (nameless,  because  they  do  not 
resemble  anything)  bones,  are  large,  flat,  and  somewhat 
semicircular  in  shape.  They  meet  in  front  (Fig.  53),  but 
behind  they  join  the  portion  of  the  spinal  column  called  the 
sacrum,  which  separates  them  and  forms,  as  it  were,  the 
keystone  of  the  arch.  Thus  is  formed  a  large  band  of  bone 
inclosing  a  basin-shaped  space,  called  the  pelvis  (basin), 
which  contains  the  bladder,  rectum,*  and  generative  organs. 
There  is  a  deep  socket  at  the  side  in  each  innominate  bone. 
This  socket  is  occupied  by  the  round  head  found  on  the 
upper  end  of  the  thigh  bone,  or  femur.  The  femur  is  the 
largest  and  longest  bone  in  the  body  (Figs.  54.  55). 


The  Skeleton  Framework  of  the  Body 


The  leg  below  the  knee,  like  the  fore- 
arm, is  composed  of  two  parallel  bones. 

They  are  unequal  in  size,  like  the  radius 

and  ulna.     One,  called  the  tibia,  is  much 

larger  than  the  other,  the  fibula  (Fig.  52). 

The  latter  bone  is  merely  a  brace  to  the 

large  tibia,  which  forms  the  joints  with  the 

femur  above  and  the  foot  below.     There 

is  a  bony  disk  embedded  in  the  great  ten- 
don over  the  knee,  form- 
ing a  protection  to  the 
knee  joint ;  this  is  called 
the  patella,  or  knee-pan. 
In  which  direction  can 
you  move  the  patella  to 
and  fro  with  the  hand, 
when  the  leg  is  straight 
and  the  heel  resting  upon 
the  floor? 

Like  the  hand,  the  foot 
consists  of  three  parts. 
The  tarsus,*  or  ankle,  is  FIQ  5J_  Front 
formed  of  seven  bones,  view  of  femur, 
although  the  carpus  has  bonTfo^artlcuiat- 

eight.      The  metatarsus,*     ing  with  hip  bone ; 

like   the   metacarpus,   is    6'  sh,aft;  c  and  f* 

rough   processes    to 
Composed   of   five   bones,     which    muscles    are 

arranged  parallel  to  one 
another,  which  serve  for    ulates  with  tibia, 
the  base  of  the  toes.    The 
toes  have  the  same  number  of  bones  as 
the  fingers,  and  have  the  same  name,  the 
phalanges. 

The  Structure  and  Hygiene  of  the  Foot.  —  It  is  important 
to  understand  what  the  human  foot  is  like,  because  abuse  of 


86 


Healthful  Living 


the  foot  is  so  common  and  the  value  of  strong,  sound  feet 
is  so  great.     The  foot  must  support  the  weight  of  the  body 

and  in  addition  must  serve 
to  transfer  the  weight  of 
the  body  from  the  heel  to 
the  toe  in  walking. 

1.    The     bones     are     ar- 

FIG.  56.  —  Skeleton  of  foot,     If  the 

child  never  goes  barefooted,  the  arch  is    ranged     to     Jorm     an     arch. 
likely  to  become  flattened  instead  of     Jn  ^Q  grg^  plac(3j  the  bones 

of  the  foot  are  arranged  to 

form  an  arch  extending  from  the  toes  to  the  heel  (Fig.  56). 
This  arch  is  low  on  the  outer  side  of  the  foot  and  here  the 
tissues  covering  the  bones  are  in  contact 
with  the  ground  (Fig.  57).  On  the  inner 
side,  however,  that  arch  is  high  and  is  held 
in  place  by  ligaments  on  its  under  surface, 
and  by  small  muscles  (Fig.  58)  attached  to 
the  bones  of  the  foot,  and  by  the  tendons 
from  the  calf  muscles  which  pass  under  this 
part  of  the  foot  on  the  way  to  the  toes.  In 
addition,  the  heel  bone  (os  calcis)  is  placed 
more  to  the  outer  side  of  the  foot.  As 
regards  the  use  of  the  foot,  these  anatomic 
facts  mean  that  the  weight  of  the  body  can 
be  carried  on  the  outer  side  of  the  foot  to 
the  best  advantage.  We  should  use  the 
body  in  conformity  with  the  laws  of  its 
construction.  In  this  way  we  shall  be 
more  efficient.  In  walking,  therefore,  the  track  made  by  a 

.    T  .     i        i  i    ^   n  ,1  •  i        p    ,1        natural  foot.  Make 

weight  should  tall  on  the  outer  side  ot  the  a  test  by  wetting 

foot  (Fig.  57).  your  foot  and  notic- 

~      rm  777  JT  7    ing  the  track  made 

2.    The  muscles  help   to  support  the  arch  upon  the  floor. 
and  the  muscles  must  be  used  correctly.     In 
the  second  place,  the  muscles  on  the  under  surface  of  the 
foot  (Fig.  58)  must  be  kept  strong  and  the  muscles  of  the 


FIG.     57.  —  The 


The  Skeleton  Framework  of  the  Body 


87 


calf,  going  to  the  toes,  must  be  exercised.  It  is  important, 
therefore,  to  walk  with  the  feet  parallel.  This  will  more 
readily  bring  the  weight  on  the  outer  side  and  in  addition 
will  allow  better  action  of  the  foot  muscles.  If  the  feet 
are  turned  outward  in  walking  (Fig.  59),  the  weight  of  the 
body  will  be  transferred  to  the  inner  side  of  the  foot  just 
over  the  arch  instead  of  passing  forward 
over  the  toes  (Fig.  60).  The  feet  should 
not  be  turned  inward,  "pigeon-toe."  The 
parallel  position  only  is  correct. 

3.  Shoes  must   not   distort    the   bony   ar- 
rangement  of   the  foot.      Shoes    must    not 
cramp  the  toes  or  press  the  toes  outward. 
This  occurs  in  pointed  shoes  and  prevents 
the    proper    action    of    the    foot    muscles 
(Fig.  61). 

4.  Shoes  must  not  throw  strain  upon  the 
foot.     If  the  foot  is   to   remain  useful  and 
efficient,  the  arch  must  not  be  subjected  to 
a  change  in  position  of  the  bones  of  the 
foot.     High  heels  throw  the  bones  of  the 
arch  out  of  position   and   prevent   proper 

foot  action  (Fig.  62).  Women  who  wear  FIG.  58.  —  Sole 
high  heeled  shoes  are  as  barbarous  in  this  %£%  the°mus- 
respect  as  the  Chinese  women  who  bound  cies  and  tendons 
thP  fApt  that  bend  the  toes 

and     support    the 

The  structure  of  a  long  bone.  —  If  a  long   arch. 
bone  is  sawed  through  lengthwise  (Fig.  63), 
it  will  be  observed  that  there  is  a  central  cavity  containing 
yellow  marrow.*     (What  cut  of  steak  has  a  marrow  bone?) 
We  should   observe  also  that   the   portions   inclosing  this 
cavity  are  of  a  dense  solid  structure,  but  that  the  bone  is 
spongy  near  the  ends,  enlarged  for  forming  the  joints.     The 
cavities  in  this  spongy  portion  contain  red  marrow.     A  long 
bone  is   hollow.      A   given   weight  of  material   has   more 


88 


Healthful  Living 


strength  in  the  form  of  a  hollow  cylinder  than  in  the  form 
of  a  solid  rod.  (Does  this  imply  that  a  hollow  cylinder  is  as 
strong  as  a  solid  one  of  the  same  size?) 
The  composition  of  bone.  —  Bone  is 
covered  with  periosteum.  This  is  the 
name  given  to  the  close  clinging  fibrous 
covering  of  the  bone,  composed  of  con- 
nective tissue  and  blood  vessels.  If  we 
remove  the  periosteum  from  the  surface, 
the  red  marrow  from  the  pores,  and  the 
yellow  marrow  from  the  larger  cavity, 
we  have  remaining  the  true  bony  sub- 
stance. Yet  even  this  is  not  one  sub- 
stance, but  consists  of  mineral  matter 
and  animal  matter  in  the  proportion  of 
two  parts  of  the 


latter.     The  animal 

matter  is  gelatin,*  like  the  substance 
composing  the  white  fibrous  part  of  con- 
nective tissue.  The  mineral  matter  is 
chiefly  phosphate  of  lime  and  carbonate 
of  lime. 

The  mineral  matter  may  be  removed 
by  soaking  the  bone  for  several  days  in 
strong  vinegar  or  in  dilute  muriatic  acid. 
The  bone  is  then  flexible  but  tough.  If 
a  slender  bone,  such  as  a  hog's  rib,  has 
been  used,  it  can  be  tied  in  a  knot  ;  after 
the  acid  has  been  washed  off,  it  may  he 
preserved  in  dilute  alcohol  as  a  curiosity,  other. 


FIG.  60.  —  In  walk- 


The    weight 


The  animal  matter  mav  be  removed  by  should  be  placed  on  the 

•      outer  borders  of  feet. 

holding  the  bone  on  a  shovel  in  the  fire 

for  a  sufficient  length  of  time.     The  mineral  part  remaining 

is  very  light  and  brittle,  and  weighs  much  less  than  the 


PLATE  IX.  —  X-ray  of  ankle,  showing  tarsus  and  lower  end  of  tibia 
and  fibula.     Notice  the  bony  arch. 


The  Skeleton  Framework  of  the  Body 


original  bone,  the  form  of  which  it  still 

preserves. 

Joints.  —  The  meeting  of  the  ends 

of  two  bones  makes  a  joint  and  this 

joint  is  held  together  by  bands  of  con- 
nective tissue,  called  ligaments.  Liga- 
ments are  composed  of  white  fibrous 

tissue.     Are    they   tough?     Are   they 

elastic  or  non-elastic?     The  way  the 

bones  are  placed  in  the  body  to  allow 

movement    is    shown    in    the    X-ray 

picture     (Plate     IX).       The    shadow 

shows  the  outline  of  the  ankle  with  the 

bones  of  the  tarsus  and  the  lower  end 

of  the  tibia  and  fibula.     The  ligaments 

holding  the  bones  to  form  the  ankle 

joint  do  not  show  in  an  X-ray.     This 

picture   indicates   how   the  bones  are 

kept  together  and  yet  are  free  to  move 

one  upon  the  other. 

Now  all  joints   are  not   alike  in  the 

movement  they  allow.    Some  have  very  little  motion  ;  others 

move  freely  and  over  quite  a  range.     The  bones  forming  the 

skull  have  practically 
no  motion  in  adult  life 
and  they  are  called 
fixed  joints.  They  are 
remarkable  in  that  the 
bones  fit  into  each 
other  by  toothed  edges, 
forming  irregular  lines, 
known  as  sutures. 
Other  joints  which  we 
shall  study  have  a  free 
type  of  movement. 


FIG.  61.  — The  track 
made  by  a  foot  in  which 
the  natural  arch  has  been 
partly  broken  down  by 
tight  shoes.  If  the  arch 
breaks  down"  entirely  the 
foot  is  called  flat  foot. 


_Jmportent 
Ligament  Supporting 
the  Arch. 


FIG.  62.  —  After  wearing  high  heels  the 
small  bones  of  the  foot  are  adjusted  to  a  cer- 
tain position.  If  a  sudden  change  is  made 
in  height  of  heel,  pain  and  disability  follow. 
Pain  in  the  knees  and  hips  follows  wearing 
high  heels. 


Healthful  Living 


Let  us  take  the  knee  joint,  for  example.  The  two  bones 
which  join  are  the  femur  and  the  tibia.  They  present  to 
each  other  an  enlargement,  or  head,  which  serves  to  increase 
the  strength  of  the  joint  and  increase  the 
surfaces  applied  to  each  other.  The 
two  heads  instead  of  being  formed  al- 
together of  rigid  bone  are  covered  by 
cartilage,  which  by  its  elasticity  and 
smoothness  provides  for  the  gliding  of 
one  bone  upon  the  other.  Strong 
fibrous  bands  called  ligaments  bind  to- 
gether the  ends  of  the  two  bones.  Sur- 
rounding the  ends  of  the  bones,  like  a 
collar,  is  found  a  ligament  (the  capsular 
ligament)  inclosing  the  space  of  the  joint 
in  a  closed  sac.  This  closed  sac  is  called 
the  capsule.  A  thin  membranous  sac, 
called  the  synovial  membrane,  lines  the 
capsule.  It  secretes  a  slimy  fluid  which 
resembles  the  white  of  an  egg  and  is 
called  the  synovial  fluid.  This  lubri- 
cates the  joint,  and  is  deposited  con- 

tinuaUy>  but  on'y  so  fast  as  used  «p  in 

length,    exercise.     As  the  sac  has  no  opening, 
cxciucied,  and  atmospheric  pres- 

,  .  ' 

porting  c,  the  upper   sure  aids  in  holding  the  bones  in  place. 

and      lower      articular    The  ^      .    ^  ^       ^  and  ^       .    { 
surfaces;     d,    compact  £ 

bone  forming  the  shaft  ;   have  the  same  parts  as  the  knee  joint. 

e,    marrow    cavity;   /,     Jt    fe    mrely    that     twQ     boneg          t    to_ 
periosteum. 

gether  so  perfectly  are  forced  from 
their  natural  places.  When  this  happens  it  is  called  a 
dislocation. 

Motion  in  movable  joints.  —  Not  all  movable  joints  can 
be  moved  in  a  similar  way.  We  can  move  the  knee  joint 
in  two  directions,  forward  and  backward.  The  shoulder 


along    its 

o.  struts  and  stays  of   air 

b,    spongy    bone    sup- 


The  Skeleton  Framework  of  the  Body 


joint  is  capable  of  more  and  wider  movements.     There  are 
four  varieties  of  movement  in  the  joints  of  the  body. 

1.  Gliding  Motion.     This  is  the  simplest  kind  of  move- 
ment.    It  is  the  rubbing  of  one  surface  on  another  and  it  is 
small   in   extent.     Ex- 
amples of  this  move- 
ment are  found  in  the 

carpal  and  tarsal  bones 
of  the  hand  and  foot. 

2.  Angular  Motion. 
This    type    of   motion 
occurs     in     only     one 
plane.      It  is   seen   in 
what  is  called  a  hinge 
joint.      Does    a    door 
swing    in    one    plane? 
The  human  body  has 
four  varieties  of  angu- 
lar movement,  two  in 
the  forward  and  back- 
ward    direction     (the 
antero-posterior*  plane 
of  the  body)  and  two 

in  a  sideward  direction      FIG.  64.  —  The  right  hip  joint.    The  hip 

(movement    from     an 

antero-posterior   plane 

of     the     body)     (Fig. 

65). 

(a)  Flexion  in  a  joint  is  always  in  an  antero-posterior 
plane  of  the  body.  The  angle  formed  by  the  parts  grows 
smaller  during  the  movement.  When  the  body  bends  for- 
ward, flexion  occurs.  Show  flexion  of  the  head,  the  fingers, 
the  knee  joint,  the  ankle  joint. 

(6)  Extension  in  a  joint  is  always  in  an  antero-posterior 
plane  and  the  angle  becomes  greater.  The  fingers  are  ex- 


bone  sawed  through  so  as  to  show  the  cup 
of  the  joint,  a,  head  of  femur  in  acetabu- 
lum  ;  6,  ilium  bone  of  pelvis;  c,  capsular  liga- 
ment; /,  femur;  i,  ischium  bone  of  pelvis; 
r,  round  ligament  of  hip  joint;  s,  sacrum. 


92  Healthful  Living 

tended  when  they  are  stretched  out  straight.     Show  flexion 
and  extension  of  the  hip  joint. 

(c)  Abduction   is    movement    outward    from    an    antero- 
posterior  plane  of  the  body  and  the  angle  increases  in  size. 


FIG.  65.  —  Diagram  of  a  cross  section  of  trunk  showing  planes  and 
directions. 


Raise  the  arm  directly  to  the  side.  This  is  abduction  of  the 
arm.  What  is  abduction  of  the  head  ?  Of  the  leg  ? 

(d)  Adduction  is  movement  toward  an  antero-posterior 
plane  of  the  body,  and  the  angle  between  the  parts  decreases 
in  size.  Show  adduction  of  the  leg. 

3.  Circumduction.  This  movement  is  a  combination  of 
flexion,  extension,  abduction,  and  adduction.  The  end  of  the 


The  Skeleton  Framework  of  the  Body  93 

moving  part  describes  a  circle  and  the  part  itself  describes  the 
sides  of  a  cone  (Fig.  66).     Show  circumduction  of  the  arm. 


FIG.  66.  —  Circumduction  —  the  extremity  (hand)  describes  a  circle 
and  the  part  describes  the  sides  of  a  cone. 

4.  Rotation.  In  this  movement,  the  moving  part  turns 
around  its  own  axis.  Show  rotation  of  the  head.  Show 
circumduction  of  the  head. 

GLOSSARY 

Antero-posterior.  —  A  compound  word  made  up  of  anterior  and 
posterior  to  denote  a  direction  or  plane  passing  from  the  an- 
terior (front)  part  of  the  body  to  the  posterior  (back).  If 
the  anterior  plane  is  a  plane  parallel  to  the  front  of  the  body 
and  the  posterior  to  the  back  of  the  body  then  it  follows  that 
there  are  innumerable  antero-posterior  planes  and  they  will 
all  be  perpendicular  to  the  anterior  and  posterior  planes. 

Bacterium.  —  The  plural  form  is  bacteria.  They  are  small  cells, 
spherical,  rod-shaped,  or  spiral  in  form.  Some  are  capable  of 
causing  disease  in  the  body,  but  most  of  them  are  harmless. 
They  are  widespread  in  nature. 

Carpus.  —  The  eight  small  bones  which  form  the  wrist. 

Condyle.  —  An  enlarged  and  prominent  part  of  a  bone. 

Environment.  —  All  the  external  surroundings  of  an  organism. 
The  air,  climate,  food,  work,  play,  housing,  clothes,  etc.,  make 
up  the  environment. 

Gelatin.  —  A  hard,  transparent,  tasteless  substance  obtained 
from  animal  tissue  such  as  skin,  hoof,  and  horns.  It  dissolves 
readily  in  hot  water. 

Marrow.  —  A  soft,  vascular  tissue  found  in  the  cavities  of  bones. 
It  contains  fat  and  many  cells  of  the  blood. 


94  Healthful  Living 

Metacarpus.  —  That   part   of   the   hand   between   the   wrist   and 

fingers.     It  comprises  five  bones. 
Metatarsus.  —  That  part  of  the  foot  between  the  ankle  and  the 

toes.     It  comprises  five  bones. 
Rectum.  —  The  lower  part  of  the  colon.     It  is  made  of  muscle 

and  mucous  membrane  and  is  richly  supplied  with  nerves. 
Tarsus.  — The  seven  small  bones  which  form  the  ankle. 


CHAPTER  VI 
HYGIENE    OF   THE    SKELETON 

I.  The  Nourishment  of  Bones. 

II.  Broken  Bones. 

III.  Dislocations  and  Sprains. 

IV.  Weak  Feet. 

Foot  exercises 

Characteristics  of  a  good  shoe 
V.  .Deformities  of  the  Spinal  Column. 
Lateral  curvature  of  the  spine 
Posterior  curvature  of  the  spine 
VI.   Posture. 

Sitting 
Lying  down 
Standing 
Walking 
VII.    Essential  Facts  in  the  Growth  and  Development  of  Bones. 


The  nourishment  of  the  bones.  —  If  a  limb  be  disused 
because  of  paralysis  *  or  long  sickness,  the  bones,  as  well  as 
the  soft  parts,  lose  in  strength  and  weight.  This  shows  that 
the  more  vigorous  circulation  which  comes  with  exercise 
helps  to  rep'air  the  osseous  tissue.  The  blood  vessels  that 
supply  the  bones  enter  from  the  inner  side  of  the  periosteum. 
We  thus  see  why  the  bone  shrinks  away  if  the  periosteum  is 
removed,  and  why  the  surgeon  *  is  careful  to  leave  as  much 
of  the  periosteum  as  possible  in  the  case  of  bones  splintered 
by  accidents. 

The  animal  matter  of  bones  is  most  abundant  in  childhood, 
and  a  child's  bones  will  bend  before  they  break.  If  broken, 
they  heal  rapidly.  The  animal  matter  is  less  abundant  in 

95 


g6  Healthful  Living 

the  aged,  therefore,  the  bones  are  brittle  and  more  easily 
broken,  and  they  take  longer  to  heal. 

Broken  bones.  —  The  two  ends  of  a  broken  bone  should 
be  brought  together  in  their  correct  position  as  soon  as 
possible,  before  inflammation  and  swelling  render  this  dif- 
ficult. Of  course,  a  surgeon  should  be  called  to  set  a  broken 
bone.  If  the  patient  has  to  be  carried  some  distance,  care 
should  be  taken  to  prevent  injury  to  the  fleshy  parts  by  the 
ends  of  the  broken  bone;  the  limb  should  be  bound  with 
handkerchiefs  to  a  strip  of  board,  or  even  to  umbrellas  or 
walking  sticks,  as  temporary  splints.  Learn  the  first  aid 
treatment  for  broken  bones  on  page  419. 

Dislocations  and  sprains.  —  A  dislocation  *  sometimes 
breaks  the  ligaments  surrounding  it,  producing  inflamma- 
tion.* This  makes  examination  of  it  difficult,  hence  there 
should  be  no  delay  in  procuring  the  necessary  skill  and 
restoring  it  to  place. 

A  sprain  *  is  an  injury  due  to  a  sudden  wrenching  or  tear- 
ing of  the  ligaments,  as  a  result  of  which  a  ligament  is  lacer- 
ated or  torn  from  its  fastenings  to  the  bone.  A  bad  sprain 
may  be  more  serious  than  a  fracture,*  and  result  in  stiffness 
or  in  permanent  weakness.  Immediate  rest  is  necessary. 
A  cold  footbath  immediately  after  spraining  the  ankle  is 
sometimes  beneficial.  If  there  is  delay  in  treatment  and 
the  joint  swells,  then  use  hot  water.  Careful  rubbing,  very 
light  at  first  and  gradually  increasing  in  vigor  from  day  to 
day,  may  shorten  the  period  of  recovery.  Learn  the  first 
aid  treatment  for  a  sprain  on  page  422. 

Weak  feet.  —  In  discussing  the  foot  it  was  pointed  out 
that  the  feet  are  very  important  parts  of  the  body.  If  we  are 
to  be  able  to  do  the  many  things  in  games  and  work  that  we 
will  want  to  do  we  must  have  strong  feet.  Feet  are  not  all 
beautiful  and  many  people  are  ashamed  of  their  feet.  That 
is  because  they  have  deformed  them  by  improper  shoes  and 
improper  methods  of  walking.  Notice  the  well-shaped  use- 


Hygiene  of  the  Skeleton 


97 


ful  feet  in  Figure  60.     What  would  happen  to  the  feet  in 
Figure  60  if  placed  in  shoes  of  the  type  shown  in  Figure  62? 
Foot  exercises.  —  To  strengthen  the  muscles  of  the  feet 
the  following  exercises  will  be  found  useful : 

1.  Stand  with  the  feet  parallel  about  three  inches  apart. 
Roll  outward  on  the  outer  borders  of  the  feet. 

2.  Stand  with  the  feet  parallel  about  three  inches  apart. 
Raise  on  toes  and  then  lower  heels  slowly  with  weight  on 
outer  borders  of  the  feet. 

3.  Walk  on  outer  borders  of  the  feet  with  the  feet  parallel. 

4.  Sitting,  —  feet  flat  and  parallel  on  the  floor,  raise  the 
arch  by  attempting  to  draw  the  toes  toward  the  heel. 

5.  Same  as  number  four  —  standing. 

Exercises  to  be  done  ten  to  twenty-five  times  daily. 

Characteristics  of  a  good  shoe.  —  The  choice  of  a  shoe  that 
will  provide  the  necessary  protection  to  the  foot  and  that  will 
not  injure  the  foot  is 
very  important.  Such 
a  shoe  will  have  a  heel 
low  and  as  broad  as 
that  of  the  wearer. 
The  sole  of  the  shoe 
should  be,  in  outline, 
essentially  the  s'ame  as 
the  outline  of  the  foot 
and  especially  it  should 
have  a  straight  inner 
line.  The  shoe  should 
fit  tightly  over  the  heel 
and  should  grip  the  foot  through  the  instep,  leaving  plenty  of 
room  in  the  region  of  the  toes.  Compare  the  illustrations 
in  Figures  67,  68,  and  69  and  keep  these  points  in  mind  when 
buying  your  next  pair  of  shoes. 

Deformities*  of  the  spinal  column.  —  This  comes  chiefly 
on  account  of  the  yielding  nature  of  the  cartilage.     The 


FIG.  67.  —  Shoes 
should  be  made  to 
fit  the  foot. 


FIG.  68.  — Feet 
should  not  be 
crowded  to  fit  the 
shoe. 


98  Healthful  Living 

extent  of  the  compressibility  of  cartilage  may  be  realized 
if  one's  height  is  measured  upon  rising  in  the  morning  and 
again  at  night,  when  the  loss  in  height  sometimes  amounts 
to  nearly  half  an  inch.  The  cartilages  between  the  vertebras 


FIG.  69.  —  The  two  figures  above  represent  young  people  who  are  victims 
of  a  custom  that  is  foolish :  the  Chinese  are  giving  up  foot-binding.  The 
lower  figure  represents  young  America,  shod  with  healthful  shoes,  and 
ready  for  work  or  play. 

are  very  thick,  so  as  to  give  flexibility  to  the  spinal  column. 
This  blessing  also  brings  with  it  a  danger  of  deformity.  If 
the  head  is  bent  forward  continuously  in  study  or  work  in- 
stead of  being  held  up,  the  upper  cartilages  are  compressed 
in  front,  the  ligaments  stretch,  and  a  deformity  of  the  neck 
may  result,  causing  the  head  to  project  forward.  Working 


Hygiene  of  the  Skeleton 


99 


with  the  desk  low  in  front,  or  working  upon  the  ground, 
may  cause  round  shoulders. 

Lateral  curvature  of  the  spine.  —  Tight  clothing  deforms 
the  ribs,  which  are  early  altered  because  of  the  long  carti- 
lages. The  binding  down  of  the 
front  ends  of  the  ribs  causes 
posterior  curvature  of  the  spine, 
with  flat  chest  and  round 
shoulders.  Lateral,  or  sidewise, 
curvature  (Fig.  70)  of  the  spine 
is  caused  by  constantly  carrying 
the  books,  satchel,  or  other 
weight  in  the  same  hand ;  by 
writing  at  a  desk  that  is  too 
high;  by  hanging  the  head  to 
one  side;  and  by  improper  and 
insufficient  food,  so  that  the 
muscles  are  weakened.  Figures 
71  and  72  show  the  improper 
and  proper  ways  to  carry 
books.  It  is  important  that 
girls,  especially,  learn  to  carry 
books  in  the  proper  way  at  all 
times. 

Posterior  curvature  of  the  spine.  —  Posterior  curvature  is 
caused  by  habitually  bending  over  the  work,  and  by  slipping 
down  in  the  seat  or  desk  (Fig.  73),  "  trying  to  sit  upon  the 
small  of  the  back."  It  is  caused  also  by  weakness  of  muscles, 
by  wearing  shoes  with  high  heels,  and  by  writing  at  a  desk 
that  is  too  low.  In  curvature  of  the  spine,  the  cartilages 
become  V-shaped  and  the  ligaments  stretched.  Shoulder- 
braces  should  not  be  worn  to  correct  round  shoulders.  If 
they  hold  the  shoulders  back  they  are  doing  the  work  of  the 
muscles  and  so  the  muscles  become  weaker  and  less  able  to 
maintain  a  good  posture.  Corrective  exercises  *  are  necessary 


FIG.  70.  —  Such  a  condition 
prevents  the  boy  or  girl  from 
playing  freely  in  games.  In 
most  cases  it  can  be  prevented  ; 
in  many,  it  can  be  corrected. 


100 


Healthful  Living 


in  many  cases,  and  they  should  be  given  by  the  teacher  of 
physical  education  or  the  school  physician:  If  an  incorrect 
posture  is  habitually  assumed  in  walking,  in  carrying  books 
or  otherwise,  one  should  not  expect  to  recover  natural  grace 
of  form  by  wearing  a  brace.  Exercise  of  the  neglected 


FIG.  71.  —  An  improper 
way  to  carry  books. 


FIG.  72.  —  By  distribut- 
ing the  books  properly  the 
posture  may  be  held  easily 
in  correct  position. 


muscles,  that  is,  opposite  muscles,  instead  of  those  that  were 
used  excessively  while  acquiring  the  deformity,  is  a  great 
aid.  Posterior  curvature  has  been  improved  by  sleeping 
on  the  back  on  the  floor  or  on  a  hard  mattress. 

Posture.  —  The  bones  are  more  or  less  flexible  in  child- 
hood, so  that  the  posture  we  assume  while  we  are  growing 
children  will  determine  and  control,  very  largely,  the  shape 
of  our  bodies  when  we  become  grown.  If  a  young  tree  is 


Hygiene  of  the  Skeleton  -  ;*\  \ , ,  \  \ '  *>>  •  ici 


bent,  it  grows  into  a  crooked  tree.     What  is  that  saying, 

"  As  the  twig  is  bent "?    There  are  four  positions 

which  must  be  cor- 
rect so  that  grace, 
strength,  and  con- 
trol of  the  body 
will  result  when  wo 
are  adults.  These 
are  the  sitting,  the 
lying,  the  standing, 


FIG.  73.  — Flat  chest, 
round  shoulders,  and 
displacement  of  vital 
organs  are  produced  by 
slipping  forward  on  the 
seat. 

and     the     walking 
positions. 

Sitting.  —  One 
should  sit  in  a  chair 
or  at  a  desk  so  that 
the  trunk  is  kept 
straight  and  any 
inclination  should 
occur  at  the  hip 
joint.  This  not 
only  looks  better 
but  it  allows  the  organs  in  the  chest  and  abdomen  to  act  in 
a  free  and  unobstructed  way.  Select  the  good  posture  in 
Figures  74  and  75, 


FIG.  74.  —  This  position  is  not  only  hygienic  but 
also  comfortable  because  the  weight  is  balanced. 


.te:  Healthful  Living 


Lying  down.  —  When  the  body  is  reclining,  all  the  muscles 
should  be  relaxed.  There  should  be  no  effort  to  hold  the 
body  in  any  particular  posture.  Does  that  mean  that  there 
is  no  instruction  as  regards  lying?  No!  The  proper  lying 
position  is  on  the  right  side  or  partially  on  the  face. 

Standing.  —  It  must  be  remembered  that  the  upright 
position  of  man  is  an  acquired  position.  A  long  time  ago 
the  ancestors  of  man  climbed  and  walked  on  "all  fours." 

It  is  also  true  that  the 
posture  of  man  differs  in 
different  races.  The  stand- 
ing posture  of  the  Chinese 
is  different  from  that  of 
the  Englishman.  The  pos- 
ture of  people  of  the  same 
race  varies  because  they 
are  expressing  different 
things  in  the  way  they 
stand.  This  is  a  very  im- 
portant fact.  The  body 
speaks  all  the  time  and 
tells  many  things  by  the 
position  it  takes  in  stand- 
ing. We  should  be  sure 
that  we  are  having  it  tell 
the  things  that  we  are 
willing  to  stand  for.  Ob- 
serve the  walk  of  people  on  the  street  and  see  if  you  can  tell 
what  the3r  are  thinking  about  or  how  they  are  feeling.  What 
do  you  express  in  your  body  as  you  walk  to  school.  The 
standing  position  in  order  to  be  most  efficient  must  be  in 
balance.  The  weight  must  be  carried  on  the  balls  of  the 
feet.  This  does  not  mean  that  the  heels  are  not  to  touch 
the  ground.  The  head  should  be  carried  on  top  of  the 
chest  and  not  projected  forward  as  if  it  grew  from  the 


FIG.  75.  —  The  sitting  posture  de- 
pends upon  proper  seats. 


Hygiene  of  the  Skeleton 


103 


FIG.  76.  —  Good  posture  makes  for  health,  happiness,  and  improves 
personal  appearance.  Write  a  legend  for  A,  B,  and  C  that  tells  what  the 
girl  is  saying  with  her  body. 


FIG'.  77.  —  The  boy  with  good  posture  is  not  only  a  stronger  and  more 
active  boy,  but  his  posture  will  be  an  asset  in  business  or  professional  life. 
A,  body  erect,  weight  over  the  balls  of  the  feet.  B,  body  relaxed,  no  control 
and  no  balance,  hence  in  a  poor  position  for  action.  C,  body  stiff  and  bent 
backward  —  awkward. 


104 


Healthful  Living 


front  of  the  chest.  Compare  the  postures  in  Figures  76 
and  77. 

Walking.  —  In  walking,  the  weight  should  be  carried  on 
the  outer  side  of  the  feet  (Fig.  57),  the  feet  should  be  placed 
on  the  ground  parallel  to  each  other  (Fig.  60),  the  chest 
should  be  carried  well  forward  (Figs.  76  A,  77  A),  and  the 
arms  should  swing  easily  at  the  side.  In  Figures  71-77  tell 
the  good  and  bad  points  in  the  postures  shown. 

If  the  habits  of  the  body  in  motion  and  at  rest  are  in- 
correct, if  the  parts  are  not  clothed  properly,  the  flexible 
bones  in  childhood  will  be  malformed.  There  are  many  who 
suffer  in  adult  life  because  they  have  worn  improper  shoes 
and  clothes,  and  have  walked  and  sat  in  incorrect  postures. 
Bow  legs  are  often  caused  by  encouraging  children  to  walk 

while  too  young.  They 
may  also  result  from  im- 
proper methods  of  feeding, 
while  infants. 

Essential  facts  in  the 
growth  and  development 
of  bones.  —  For  proper 
growth  and  development, 
the  bones  must  be  used 
correctly.  Any  constant 
incorrect  use  will  show  in 
distorted  and  crooked 
bones,  producing  a  form 
that  is  less  able  to  move 
quickly  and  easily,  and 
hence  a  form  that  is  less 
efficient.  Good  food  and 

pure  air  brought  by  a  vigorous  circulation  are  essential. 
Poor  or  indigestible  food,  stimulants,*  and  poisons  affect 
the  health  and  strength  of  the  bones.  Surgeons  report  cases 
of  fracture  occurring  in  persons  having  the  alcohol  habit, 


FIG.  78.  — Appearance  of  the  face  of  a 
boy  who  did  not  have  his  adenoids  re- 
moved. (By  courtesy  of  Dr.  Frank  S. 
Mathews.) 


Hygiene  of  the  Skeleton  105 

where  the  bones  would  not  unite  by  bony  material,  but 
remained  flexible  and  useless.  Indulgence  in  alcoholic 
liquors,  especially  wine,  is  a  very  common  cause  of  gout,  a 
disease  of  the  joints.  Smoking  in  boyhood  often  prevents 
the  proper  development  of  the  long  bones  and  a  stunted 
stature  results.  It  must  also  be  remembered  that  growing 
parts  are  deformed  by  conditions  that  interfere  with  proper 
functioning.  In  this  way,  adenoids  may  cause  marked 
deformity  of  the  bones  of  the  face  (Fig.  78). 


APPLIED   PHYSIOLOGY 

Exercise  I 

1.  What  are  the  common  faults  found  in  shoes  and  how  do  such 
shoes  injure  the  feet?     Most  people  assume  the  following  rule 
in  selecting  a  shoe :      If  you  can  just  draw  on  a  shoe  without 
much  effort  and  sit  with  it  on  the  foot  for  ten  minutes,  it  will  be 
comfortable  to  walk  in  and  wear  all  day.     Yet  such  a  shoe  is  one 
size  too  small  for  walking.     Many  makers  no  longer  number  their 
shoes  plainly  because  of  the  vanity  of  some  purchasers.     A  new 
shoe  should  be  as  comfortable  as  an  old  one.     Persons  who,   be- 
cause of  silly  jokes  about  big  feet  or  for  other  reasons,  have  the 
idea  that  the  shoe  should  leave  no  extra  room,  but  should  fit  as 
if  it  were  covering  a  wooden  foot,  will  always  get  uncomfortable 
shoes. 

2.  If  a  shoe  is  too  loose,  it  slips  up  and  down  at  the  heel  and 
chafes  the  sldn  there.     If  too  tight,  there  is  pressure  on  the  toes, 
which  causes  a  corn  or  ingrowing  nail.     Have  your  shoes  been 
correct  or  have  they  been  too  loose  or  too  tight  ? 

3.  How   many   sprained    ankles  have  you  known  of?     Were 
the  sufferers  mostly  boys  or  girls?     Why? 

4.  What  is  the  general  arrangement  of  the  bones  of  the  foot? 
Does  the  weight  of  the  body  come  upon  the  middle  of  the  arch? 
How  can  this  arch  be  injured  and  what  is  such  a  deformity  called? 

5.  Why  is  it  that  people  who  grow  up  in  warm  climates  are 
more  likely  to  have  high  arched  insteps  and  elastic  feet  than  those 
who  pass  their  childhood  in  cold  climates  ? 


io6  Healthful  Living 

Exercise  II 

6.  What  in  the  composition  of  a  bone  gives  it  stiffness  ?  hard- 
ness?  toughness?  flexibility? 

7.  Should  chairs  and  benches  have  straight  backs  ? 

8.  Why  is  a  chair  back  that  is  very  slanting  often  injurious? 
Why  is  a  very  deep  chair  injurious  if  deep  enough  for  the  front 
edge  to  strike  the  occupant  behind  the  knee  ? 

9.  Why  does  a  young  child  usually  crawl  before  it  walks? 

10.  Which  girdle  is  attached  directly  to  the  spinal  column? 
Which  girdle  is  attached  indirectly  ? 

11.  Why  is  the  arm  so  often  dislocated  at  the  shoulder? 

12.  High  pillows  may  cause  what  deformity? 

13.  Should  a  young  child  be  urged  to  stand  or  walk? 

14.  What  part  of  a  long  bone  is  composed  of  compact  tissue? 
Of  very  porous  tissue  ? 

Exercise  III 

15.  Could  the  neck  be  broken  and  death  result  without  break- 
ing a  bone  ? 

16.  What  would  be  the  result  if  the  ligaments  were  composed  of 
the  yellow  fibers  of  connective  tissue  instead  of  the  white  fibers? 

17.  If  a  child's  feet  be  allowed  to  dangle  from  a  high  seat,  what 
will  be  the  effect  ? 

18.  When  the  palm  is  turned  upward  is  the  radius  parallel  or 
crossed  with  the  ulna?     When  the  back  of  the  hand  is  up? 

19.  Why  should  one  always  sit  and  walk  erect  ? 

20.  In  a  long  bone  what  is  chiefly  a  storage  tissue,  saving  food 
for  future  use? 

21.  Ligaments  are  of  very  slow  growth.     This  accounts  for  the 
tedious  nature  of  the  recovery  from  what  kind  of  accidents? 

22.  Observe  how  many  of  your  classmates  sit  "  slid  forward  " 
in  the  seat,  and  report  in  recitation  the  result  of  your  count. 

23.  When  the  school  is  marching  out,  count  those  who  walk 
with  the  head  protruded. 

24.  A  "  bone  felon  "  is  often  caused  by  an  infection  beneath 
the  periosteum.     Why  should  it  be  lanced  ? 

25.  What  is  the  first  aid  treatment  for  a  fracture?     A  sprain? 

Exercise  IV 

26.  Is  it  correct  to  walk  with  the  weight  on  the  outer  side  of 
the  foot?     Why? 


Hygiene  of  the  Skeleton  107 

27.  Determine,  by  placing  the  wet  feet  on  a  piece  of  paper, 
where  the  weight  comes.     Let  the  weight  sag  inward  and  observe 
how  this  position  increases  the  size  of  the  imprint. 

28.  Make  a  tracing  on  paper  of  the  feet  in  an  abducted  posi- 
tion and  in  a  parallel  position. 

29.  Measure  your  height  in  the  morning  and  evening  of  the 
same  day.     Is  there  a  difference? 

30.  Notice  the  difference  in  breathing  while  in  the  correct  and 
incorrect  sitting  position. 

LABORATORY  EXERCISES 

Experiment  1.    To  study  the  organic  and  inorganic  *  parts  of  bone. 

Material.  —  Hog's  rib,  glass  beaker,  dilute  muriatic  acid,  and 
alcohol. 

Method  and  observation.  —  Place  the  rib1  free  from  all  muscle 
and  connective  tissue  in  the  beaker  and  cover  with  the  acid.  Leave 
in  the  acid  until  the  bone  becomes  elastic.  When  the  mineral 
(inorganic)  matter  has  been  dissolved,  the  bone  can  be  easily  bent. 
Remove  the  excess  of  acid  and  preserve  the  rib  in  alcohol. 
Experiment  2.  To  study  the  foot  in  relation  to  the  shoe. 

Material.  —  White  paper,  ruler,  and  pencil. 

Method  and  observation.  —  Place  the  bare  foot  on  the  paper 
and  draw  an  outline  of  the  foot.  Measure  with  the  ruler  the  width 
of  the  foot  in  the  instep  region  and  the  length  of  the  foot  from  toe 
to  heel.  Measure  the  width  of  the  shoe  in  the  same  region  as  that 
taken  for  the  foot ;  measure  the  length  of  the  shoe.  Compare 
the  two  sets  of  measurements. 
Experiment  3.  To  determine  the  proper  height  of  the  school  seat. 

Material.  —  Ruler  or  yardstick. 

Method  and  observation.  —  With  the  foot  flat  on  the  floor  measure 
the  length  of  the  leg  from  the  floor  to  the  under  surface  of  the 
knee.  How  many  inches  is  it?  Measure  the  height  of  the  seat 
from  the  top  of  the  forward  edge  to  the  floor.  How  many  inches 
is  it?  The  leg  measurement  should  be  one  inch  more  than  the 
seat  measurement.  Are  your  school  seats  adjustable.  Are  they 
properly  adjusted? 

GLOSSARY 

Corrective  exercises.  —  Exercises  usually  of  a  passive  type  at 
first  and  later  of  an  active  type  for  the  purpose  of  correcting 
deformities  of  the  skeleton. 


io8  Healthful  Living 

Deformity.  —  A  change  from  the  normal. 

Dislocated  —  Displaced.  The  term  here  refers  to  the  displace- 
ment of  a  bone  from  its  normal  position  in  a  joint.  When 
there  is  a  dislocation,  there  results  a  deformity. 

Fracture.  —  A  break.  Used  with  reference  to  bones.  A  broken 
bone  is  called  a  fracture.  In  a  fracture,  the  deformity  may 
not  be  seen  except  by  an  X-ray. 

Inflammation.  —  A  process  in  the  body  characterized  in  most 
cases  by  heat,  redness,  swelling,  and  pain  in  the  part  affected. 

Inorganic.  —  Not  being  or  having  been  a  living  organism.  Refers 
to  substances  in  chemistry  that  relate  to  the  world  of  metals 
and  their  compounds. 

Paralysis.  —  Loss  of  the  power  of  contractility  in  the  voluntary  or 
involuntary  muscles  of  the  body. 

Sprain.  —  The  injury  to  ligaments  of  a  joint.  This  may  be  a 
stretching,  or,  if  severe,  a  real  tearing.  The  word  strain  is 
applied  to  the  same  sort  of  injury  occurring  in  muscle. 

Stimulant.  —  A  substance  that  excites  action  in  the  body  whether 
acting  on  the  nerves  through  the  skin  or  after  getting  into  the 
circulation.  Typical  stimulants  acting  on  different  parts 
and  in  various  ways  are  spices,  mustard,  camphor,  ammonia, 
strychnin,  light,  heat,  electricity,  joy,  hope. 

Surgeon.  —  One  who  by  training,  skill,  and  experience  is  able  to 
treat  injuries  and  conditions  of  abnormality  by  means  of 
manual  methods  or  by  the  use  of  instruments. 


CHAPTER  VII 

THE     MUSCLES   AS   THE    MOTOR    MACHINERY    OF 
THE   BODY 

I.   What  the  Muscles  Do. 
II.   Muscles  and  Nerves. 

III.  Kinds  of  Muscles. 

Voluntary 

Involuntary 

Cardiac  muscular  tissues 

IV.  Voluntary  and  Involuntary  Muscles  Compared. 
V.    The  Attachment  of  Muscles. 

VI.    How  Muscles  and  Bones  Cooperate. 
VII.   Names  and  Positions  of  Muscles. 


What  the  muscles  do.  —  We  have  learned  that  motion 
is  one  of  the  properties  of  protoplasm.  What  are  the  other 
properties?  A  very  interesting  fact  of  physiology  is  that 
the  cells  of  the  body,  such  as  muscle,  nerve,  skin,  and  bone 
cells  and  the  cells  of  the  different  organs,  have  become 
specialized  through  the  development  of  a  certain  property 
at  the  expense  of  other  properties.  For  example,  the  muscle 
cell  has  developed  to  a  high  point  of  efficiency  the  property 
of  contraction ;  the  nerve  cell  has  specialized  in  conductivity 
and  irritability.  This  specialization  of  function  was  re- 
ferred to  under  the  head  of  division  of  labor.  How  does 
this  same  principle  work  in  the  society  of  men?  Movement 
of  the  body,  which  is  made  possible  by  this  specialization 
of  muscle,  is  one  of  the  essentials  of  life.  The  individual  who 
cannot  move  is  handicapped  greatly,  and  the  ability  to  move 

109 


no  Healthful  Living 

easily,  gracefully,  and  with  the  body  in  control  is  greatly  to 
be  desired. 

Muscles  and  nerves.  —  Now,  the  one  essential  condition 
for  contraction  of  the  muscles  is  stimulation  by  the  nerves. 
If  an  impulse  is  not  sent  to  the  muscle,  the  muscle  cannot 
contract.  Therefore,  it  must  be  remembered  that  the 
muscle  and  its  nerve  are  to  be  thought  of  as  a  unit.  For 
this  reason  the  strength  of  a  muscle  is  not  dependent  en- 
tirely upon  its  size.  People  who  think  that  large  muscles 
are  a  sign  of  health,  and  that  large  muscles  give  strength  and 
vigor,  are  very  much  mistaken,  if  they  depend  only  upon 
muscular  strength.  The  development  of  the  will  is  very  im- 
portant. The  body  has  been  compared  to  a  steam  engine. 
To  what  parts  of  the  engine  may  the  muscles  be  compared  ? 

We  are  hearing  a  great  deal  to-day  about  eugenics.*  This 
word  means  "  favorable  birth."  The  eugenic  movement 
aims  to  improve  the  physical,  mental,  and  moral  qualities 
of  the  race.  It  seeks  to  improve  the  quality  of  life  in  the 
nation.  Now  muscle  and  nerve  tissues  will  have  a  good 
heredity,*  they  will  be  strong  and  efficient  in  proportion  to 
the  vigor  and  strength  of  the  protoplasm  from  which  they 
come.  The  science  of  eugenics  aims  at  ends  which  should 
encourage  all  thoughtful  young  persons  so  to  live  that  they 
will  keep  strong  and  healthy. 

Kinds  of  muscles.  —  Muscular  tissue  occurs  in  nearly  every 
organ.  It  helps  to  form  the  walls  of  the  blood  vessels,  and 
assists  in  the  circulation  of  the  blood  ;  the  eyeballs  are  moved 
by  six  sets  of  muscles ;  the  act  of  swallowing  is  performed 
by  muscular  contraction  in  the  esophagus ;  the  contrac- 
tion of  the  muscles  in  the  walls  of  the  stomach  produces  the 
motion  by  which  the  food  is  mixed ;  in  the  intestines  the 
muscles  keep  the  partly  digested  food  in  motion  ;  the  muscles 
in  the  limbs  enable  us  to  move  and  work ;  the  heart  is  chiefly 
muscle ;  the  muscles  in  the  chest  and  trunk  enable  us  to 
breathe ;  those  in  the  larynx  are  used  in  talking. 


The  Muscles  as  the  Motor  Machinery  of  the  Body     in 


Muscles  Have  been  divided  into  two  classes,  voluntary 
and  involuntary.  The  first  class  is  under  the  control  of  the 
will,  either  at  all  times  or  part  of  the  time;  the  second  is 
never  under  the  control  of  the  will ;  their  work  goes  on  quite 
independently  of  the  will  and  even  during  sleep.  Can  you 
assign  to  their  proper  classes  the 
muscles  named  in  the  preceding 
paragraph  ? 

Voluntary  (striated)  muscles.  — 
It  is  to  be  remembered  that  a 
muscle  is  made  up  of  cells  which 
are  specialized  to  perform  the 
function  of  contracting.  For  the 
carrying  out  of  this  purpose,  they 
have  developed  fibers  within  their 
protoplasm.  The  contraction  of  a 
muscle  is  caused  by  the  contrac- 
tion of  the  individual  fibers  which 
compose  it.  Each  fiber  shortens  in 
length  and  becomes  proportionally 
thicker ;  the  sum  total  of  the  con- 
tractions of  these  fibers  taking 
place  at  the  same  time  makes  up 
the  contraction  of  the  whole  muscle. 
The  number  of  fibers  lying  side  by 

.,      ,    ,                    xu     xi  •   i               /•  xi  FlG-    79. —A    portion    of 

Side  determines  the  thickness  of  the  three   striated   muscle  fibers, 

muscle,  and  the  amount  Of  Strength  moderately  magnified.    Show- 

vu       u-   u    -4.                                          u-i  ing      the      capillary      vessels 

with  which  it  can  contract;  while    (dark). 

the  number  of  fibers  lying  end  to 

end  determines  the  amount  of  shortening  or  contraction  of 

which  the  muscle  is  capable.     When  the  muscle  is  habitually 

used,  it  becomes  larger,  finer,  darker,  and  stronger. 

Voluntary  and  involuntary  muscles  are  not  constructed 
exactly  alike.  Examined  under  the  microscope,  each  fiber 
of  a  voluntary  muscle  shows  bright  bands  alternating  with 


ii2  Healthful  Living 

dark  bands,  running  across  it  (Fig.  79).  These  bands  give 
the  whole  muscle  a  striated  or  striped  appearance  under 
the  microscope,  and  this  kind  is,  therefore,  called  striated 
muscle.  The  fibers  are  bound  together  by  connective 
tissue  into  bundles  called  fascicles  and  these  again  into 
larger  bundles.  The  connective  tissue  surrounding  the 
bundles  can  be  plainly  seen  in  chipped  beef,  also  in  raw  or 
boiled  beef.  The  voluntary  muscles  are  darker  red  than 
the  involuntary.  Lean  meat  is  made  up  of  these  muscles. 
They  are  near  the  surface,  but  their  outlines  under  the  skin 
are  obscured  to  a  greater  or  less  degree  in  different  persons, 
according  to  the  thickness  of  the  layer  of  fat  between  the 
muscles  and  the  skin.  These  muscles  are  usually  attached 
to  bones.  They  contract  quickly,  while  the  involuntary 
muscles  contract  slowly. 

Involuntary  muscles  (non-striated,  smooth).  —  Involuntary 
muscles  are  found  in  the  walls  of  the  alimentary  canal,  the 

bladder,  the  esophagus, 
and  several  other  organs; 
all  such  muscles  are  com- 
posed of  fibers  which  are 
not  striated,  and  are, 
therefore,  called  plain 
muscle  fibers.  A  striated 

FIG.  80.  —  Fibers  of  non-striated 

muscles,  or  involuntary  muscles.  fiber   is  about  One   inch   in 


length  and  -g-J^  of  an  inch 

in  thickness  and  is  shaped  somewhat  like  a  cylinder;  it 
possesses  several  nuclei.  A  non-striated  muscle  fiber  is  not 
more  than  ^^  of  an  inch  in  length,  has  the  form  of  a  very 
slender  spindle,  and  contains  one  nucleus  (Fig.  80).  The 
fibers  interlace  and  are  held  together  by  fine  connective 
tissue. 

Cardiac  muscular  tissue.  —  Cardiac*  muscular  tissue,  'of 
which  the  heart  consists,  differs  from  both  striated  and  plain 
muscular  tissue  (Fig.  81).  Its  fibers  possess  one  nucleus, 


The  Muscles  as  the  Motor  Machinery  of  the  Body     113 


FIG.    81.  — Two 


like  plain  fibers ;  they  are  not  spindle-shaped  and  narrow, 
however,  but  broader  and  cylindrical.  They  are,  more- 
over, faintly  cross-striated  by  light  and  dark 
bands.  We  may  say,  therefore,  that  al- 
though the  heart  is  in  every  respect  an  in- 
voluntary muscle,  it  has  more  resemblance 
to  striated  than  to  plain  muscles.  The 
many  muscles  used  in  breathing  are  at 
times  voluntary,  and  at  other  times  in- 
voluntary ;  but  they  are  all  striated  muscles 
with  the  usual  structure. 

Voluntary  and  involuntary  muscles  com- 
pared. —  Compare   the   voluntary  and  in- 
voluntary muscles  by 

Writing    in    two    Col-    cardiac   muscle    fi- 

umns  headed,  Volun-  ^ne  "j  junction 

tary      Muscles      and    between    the    two 

InvoluntaryMuscles,  ^sing  \  ^Sar 

the  facts   concerning   process  of  another 

their  Control,  Struc-  °el1  (magnified  40° 

diameters). 

ture,  Color,  Position 
in  Body,  Attachment,  Rate  of  Con- 
traction, Number  of  Nuclei,  Length 
of  Fibers,  Breadth  of  Fibers,  Shape 
of  Fibers.  (Place  these  titles  in  a 
third  column.) 

The  attachment  of  muscles.  —  The 
involuntary  muscles  are  usually  found 
in  the  wall  of  organs  that  have  cavi- 
ties. Thev  are  sometimes  called  the 


in  tendon  (6) .    Many  other   visceral  muscles  because  the  internal 

Sn™^  *****  *  ***    OrganS    are    CalM    the   V™*™'      The 

quicker,     stronger-acting    voluntary 

muscles  are  called  the  skeletal  muscles  because  nearly  all  of 
them  are  attached  to  bones.    There  are  about  five  hundred 


Healthful  Living 


voluntary  muscles.  By  studying  the  figures  you  will  notice 
that  the  middle  portion  of  these  muscles  is  usually  large  and 
full,  and  that  the  muscles  taper  to  small  cords  at  the  ends 
(Fig.  82).  The  muscles  of  the  calf  move  the  foot,  and  the 
muscles  of  the  forearm  move  the  hand.  If  the  full  round 
muscles  extended  down  over  the  wrists  and  ankles,  it  would 
make  these  as  large  around  as  the  forearm  or  calf,  and  the 
wrists  and  ankles  would  be  very  clumsy  and  awkward.  It 
is  found  that  the  connective  tissue  which  binds  the  fibers  of  a 
muscle  into  bundles  and  forms  sheaths  for  the  bundles,  extends 
beyond  the  muscular  tissue  and  unites  to  form  a  dense,  in- 
elastic, glistening  white  cord  called  a  tendon.  The  fibers 
are  very  closely  packed  together  and  make  a  very  strong 
cord.  One  no  thicker  than  a  lead  pencil  is  strong  enough 
to  support  twice  the  weight  of  the  body.  A  tendon  contains 
no  nerves  and  very  few  blood  vessels.  Some  muscles  have  a 
tendon  at  only  one  end ;  some  have  no  tendon  but  are  at- 
tached directly  to  bones. 
Find  muscles  without 
tendons  by  studying  the 
figures.  The  cordlike 
nature  of  tendons  can 
be  ascertained  by  feel- 
ing the  tendons  under 
the  knees,  called  ham- 
strings, or  the  tendons 
in  the  angle  of  the 
elbow. 

How  muscles  and 
bones  cooperate. — 
When  you  grasp  a  heavy 
weight  in  the  hand  and 
lift  it  by  bending  the 

elbow,  where  is  the  muscle  that  does  the  work?     You  will 
easily  find  it  in  the  upper  arm.     This  muscle  is  called  the 


FIG.  83.  —  Diagram  to  show  the  action 
of  the  biceps  muscle  of  the  arm.  The  two 
tendons  by  which  the  muscle  is  attached  to 
the  scapula  are  seen  at  s ;  r,  the  point  of 
attachment  of  the  muscle  to  the  radius; 
e,  the  elbow  joint ;  h,  the  weight  of  the 
hand. 


The  Muscles  as  the  Motor  Machinery  of  the  Body     115 

biceps  because  it  is  attached  to  the  shoulder  blade  above  by 
two  tendons.  The  lower  arm  acts  as  a  lever  *  with  the  ful- 
crum,* or  fixed  point  of  the  lever,  at  the  elbow  (Fig.  83).  It 
is  easy  to  see  that  a  slight  contrac- 
tion of  the  biceps  muscle  will  move 
the  weight  a  greater  distance  than  is 
accounted  for  by  the  shortening 
caused  by  the  actual  contraction  of 
the  muscle.  This  is  what  the  bones 
usually  accomplish  for  the  muscles ; 
they  change  a  slow,  short,  inade- 
quate movement  into  a  long,  swift 
movement.  While  the  muscle  con- 
tracts an  inch,  the  bone  may  move 
a  foot.  The  bones  thus  add  greatly  to  the  range  and  rate 
of  motion. 

Figures  84, 85  and  86  show  the  three  orders  of  levers.  In  the 
lever  of  the  first  order,  the  fulcrum  (F)  is  between  the  power 
(P)  and  the  weight  (W).  In  the  lever  of  the  second  order 
the  weight  is  between  the  other  two,  and  in  the  lever  of  the 


Power 


FIG.  84.  —  Tapping  floor 
with  toe.  Lever  of  first 
order. 


Fulcrum 


Weight 


FIG.  85.  —  Raising  weight 
of  body  upon  ankle.  Lever 
of  second  order. 


Fulcrum 


FIG.  86.  —  Raising  a 
weight  upon  toes.  Lever 
of  third  order. 


third  order  the  power  is  between  the  others.  In  Figure  83 
the  biceps  muscle  acts  on  the  radius  and  ulna  fastened  to- 
gether as  one,  turning  at  the  elbow  as  a  fulcrum ;  the  weight 
to  be  lifted  is  in  the  hand.  This  is  evidently  a  lever  of  the 


n6 


Healthful  Living 


third  order  with  the  power  between  the  other  points.  In 
this  case  it  takes  a  force  in  the  muscle  equal  to  about  six 
pounds  to  raise  one  pound  in  the  hand. 

Figure  87  shows  how  the  muscles  may  act  upon  the  bones 
as  levers  to  prevent  the  bones  from  turning  upon  the  joints 


FIG.  87.  —  Diagram 
of  the  muscles  that 
keep  the  body  erect. 


stoid 


FIG.  88.  —  Muscles  of  head  and 
neck.  Find  the  following  muscles : 
Chewing  muscles ;  scalp  muscles ; 
bowing  muscle  of  one  side ;  muscle 
that  holds  head  erect  (upper  part  of 
trapezius  at  back  of  neck) ;  muscle 
that  squints  the  eye ;  muscle  that 
pouts  the  lips ;  muscle  that  broadens 
the  mouth  in  smiling ;  muscle  that 
raises  corners  of  mouth ;  muscle  that 
draws  down  corner  of  mouth. 


as  fulcrums;  thus  the  body  is  held  erect.  Where  are  the 
muscles  located  that  keep  the  body  from  falling  or  bending 
forward?  From  falling  backward?  Which  of  the  two  sets 
is  in  front?  What  kind  of  lever  is  illustrated  by  the  head 
tilted  upon  the  first  vertebra? 


The  Muscles  as  the  Motor  Machinery  of  the  Body     117 

Names  and  positions  of  muscles.  —  A  few  of  the  important 
muscles  are  here  mentioned :  The  scalp  muscle  (Fig.  88) 
passes  over  the  top  of  the  head ;  it  raises  the  skin  over  the 
eyes,  and  (in  some  persons)  moves  the  scalp.  The  two  pairs 
of  chewing  muscles  are  the  temporal  *  and  masseter  *  (Fig.  88) . 
You  can  feel  the  temporal  muscle  swell  and  harden  if  you 


Trapes/us 


•Jtoid 


Latissimus 


FIG.  89.  —  Principal  muscles  of  the  back.  Trapezius  draws  shoulder 
and  head  back ;  deltoid  raises  whole  arm ;  latissimus,  climbing  muscle ; 
obliquus  internus  and  obliquus  externus  draw  abdominal  wall  in  and  force 
abdominal  contents  against  the  diaphragm,  thus  expelling  air  from  lungs. 

place  your  finger  on  the  temple  and  close  your  mouth  forcibly. 
In  the  same  manner  you  may  feel  the  contraction  of  the 
masseter  by  placing  the  fingers  just  below  the  cheek  bone. 
The  muscle  used  in  bowing  passes  obliquely  down  on  the 
side  of  the  neck  to  the  collar  bone  (Fig.  88).  It  can  be 
felt  as  a  thick  band ;  when  the  head  is  turned  to  one  side,  it 
stands  out  as  a  ridge.  When  one  of  the  two  acts  alone,  it 
turns  the  face  so  as  to  look  to  the  other  side.  When  both 
act,  they  bow  the  head.  The  deltoid  *  (Fig.  89),  or  shoulder 


n8  Healthful  Living 

cap  muscle,  raises  the  whole  arm  outward  and  upward  from 
the  side.  Can  you  locate  it  by  the  feeling  of  fatigue  after 
raising  the  arm  twenty  times?  The  biceps  can  be  seen  and 
felt  contracting  on  the  front  of  the  arm  when  bent  at  the 
elbow.  The  triceps*  is  on  the  opposite  side  of  the  arm  and 

•Extensors  of  the  Hand 
•flexors  oftheffand 


Trrceps 


-PectoraNs-  Maic 
De/toid-  ~ —  "" 


Serratus  Afatjnus- 

-Rectus  Abdominal/ s 


Pectus  Femorfs  - 

\HPB«VifiS3Bii 

-Vastus  Externus 

Hr 

Tibiatis  Anticus' 

//m\ 

-Extensors  of  the  Toes 
FIG.  90.  —  Full-figure  muscles  (front) . 

straightens  the  elbow  (Fig.  92).     Which  is  used  in  striking 
a  blow,  the  biceps  or  the  triceps  ? 

The  sartorius*  (tailor)  muscle  (Fig.  90)  is  nearly  two  feet 
long  and  is  the  longest  muscle  in  the  body ;  it  passes  from  the 
outer  side  of  the  hip  bone  to  the  inner  side  of  the  leg  below 


The  Muscles  as  the  Motor  Machinery  of  the  Body     119 

the  knee,  and  is  used  in  crossing  the  leg;  because  of  the 
position  assumed  by  a  tailor  at  work  it  is  named  the  tailor's 
muscle.  The  gastrocnemius*  is  a  thick  muscle  in  the  calf 
of  the  leg,  which  raises  the  heel  (Fig.  91).  When  is  it  used? 
It  is  attached  to  the  heel  by  the  largest  tendon  in  the  body, 


Extensors  of 
(he  Hand 


<Trapezhj$ 

•^MiHBK^^ff^l  BO          / 

Triceps 

•Dettoid 


Latissimus  Dorsr 


Vastus  Externus 


TendoAchilfis 


FIG.  91.  —  Full-figure  muscles  (rear). 

called  the  "  tendon  of  Achilles."     Ask  the  teacher  why  it  is 
so  called,  or  read  the  story  of  Achilles. 

The  trapezius*  (four-sided)  (Figs.  89  and  91)  is  a  large 
muscle  covering  the  back  between  the  shoulders.  It  draws 
the  shoulders  back  and  holds  up  the  head.  Can  you  find 


I2O 


Healthful  Living 


the  climbing  muscle  (Fig.  89),  or  the  muscle  that  draws 
the  arm  backward  and  downward  (latissimus  or  broadest)  ? 
When  a  person  hangs  by  the  hands,  it  helps  to  raise  the  body. 
It  is  a  large  spread-out  muscle  extending  from  the  humerus 
to  the  vertebral  column. 

There  is  a  great  fan-shaped  muscle  called  the  pectoralis 
(Fig.  92),  which  attaches  the  arm  to  the  front  wall  of  the 


Tr/cepi 


Sterno-M&stofd 
Trspezfus 


JDe/tofd 


External 
Ob/ique 


FIG.  92.  —  Superficial  view  of  muscles  of  upper  part  of  trunk, 
from  the  front  (Allen  Thomson). 


thorax.  Muscles  are  arranged  in  opposing  sets.  Flexors 
oppose  extensors,  abductors  act  against  adductors.  Two 
muscles  with  opposite  action  or  function  are  said  to  be  an- 
tagonists.* When  antagonistic  muscles  work  together  in 
harmony,  then  the  movement  is  graceful.  Awkwardness 
results  from  too  strong  contraction  of  one  of  the  antagonistic 
groups.  In  learning  a  new  movement,  more  muscles  than 
are  necessary  are  used  at  first.  The  beginner  in  skating,  for 


The  Muscles  as  the  Motor  Machinery  of  the  Body     121 

< 

example,  should  not  try  too  hard,  should  not  be  too  tense, 
and  the  coordination  will  come  quicker. 

Muscles  are  named  from  their  shape,  as  deltoid  (like  the 
Greek  letter  delta,  A) ;  their  location,  as  tibialis  (near  ,the 
tibia) ;  their  action,  as  flexors ;  their  manner  of  attachment, 
as  triceps  (three-headed). 


GLOSSARY 

Antagonist.  —  In  muscles,  a  muscle  that  acts  counter  to  another 

muscle. 
Cardiac   muscle.  —  The   muscle  of   the  heart.     The  word   comes 

from  the  Greek  word  kardia  meaning  heart. 
Deltoid.  —  The  muscle  that  covers  the  point  of  the  shoulder.     So 

called  because  of  its  shape.     It  is  triangular  like  the  Greek 

letter  delta. 
Eugenics.  —  The  science  of  improving  the  human  race.      Term 

first  used  by  Sir  Francis  Galton. 
Fulcrum.  —  The  support  on  which  a  lever  rests  and  by  means  of 

which  it  obtains  its  power. 
Gastrocnemius.  —  A  large  muscle  of  the  leg  so  called  because  of 

its  large  belly   (from  Greek  gaster}  and  its  situation  on  the 

lower   leg    (from    Greek    knemis,  meaning   greave,  or    kneme, 

meaning  lower  leg). 
Heredity.  —  The  tendency  shown  by  an  organism  to  develop  in 

the  likeness  of  its  forbear. 
Lever.  —  Usually  a  straight  bar  turning  on  a  fixed  point  as  the 

fulcrum  and  serving  to  produce  a  pressure  from  the  power 

moving  the  lever  to  the  weight  or  resistance  to  be  moved. 
Masseter.  —  A  muscle  of  the  jaw  used  in  chewing.     So  called 

because  of  its  function,  from  the  Greek  word,  maseter,  a. chew. 
Sartorius.  —  A  long  muscle  of  the  thigh ;    so  called  from  its  use  in 

crossing  the  legs,   as  of  tailors.     Sartor  meaning  a  patcher, 

hence  a  tailor. 
Temporal.  —  A  muscle  that  is  located  at  the  side  of  the  head  near 

the  temple. 
Triceps.  —  A  muscle  at  the  back  of  the  upper  arm.     It  has  three 

heads. 
Trapezius.  —  A  large  flat  muscle  of  the  back  shaped  like  a  trapezoid 

when  the  two  muscles  are  viewed  together. 


CHAPTER  VIII 

THE  MUSCLES   IN  ACTION   AND   THE   HYGIENE   OF 
EXERCISE 

I.   The  Neuro-muscular  Mechanism. 

Response  of  the  muscle  to  the  nerve  stimulus 
Coordination  of  muscles 
II.   Muscular  Energy. 
Production 
Expenditure 

III.  Muscular  Tone. 

IV.  Muscular  Activity  and  Fatigue. 

V.  The  Effect  of  Stimulants  and  Narcotics  on  Muscular  Action. 

VI.  The  Effect  of  Exercise  on  Growth. 

VII.  The  Relation  of  Exercise  to  Health. 

VIII.  Forms  of  Exercise. 

IX.  Over-development  of  the  Muscles. 


The  neuro-muscular  mechanism.  —  If  the  nerve  to  the 
muscle  is  severed,  the  muscle  cannot  be  contracted  no 
matter  how  hard  we  try.  Is  a  muscle  and  its  nerve  a  unit  ? 
This  unity  is  sometimes  called  the  neuro-muscular  mech- 
anism. If  this  mechanism  is  called  psycho-motor,  *  to  what 
does  it  refer?  Does  neuro-muscular  refer  to  structure? 

Response  of  the  muscle  to  the  nerve  stimulus.  —  When  a 
muscle  cell  receives  a  stimulus  from  its  nerve,  it  changes  its 
shape  by  growing  shorter;  it  does  not  increase  in  size. 
When  a  boy  shows  his  muscle  by  flexing  his  elbow,  the  biceps 
muscle  shortens  and  becomes  thicker  in  one  part,  but  the 
entire  muscle  does  not  take  up  more  room  than  it  did  when 
in  a  relaxed  condition. 

122 


The  Muscles  in  Action  and  the  Hygiene  of  Exercise     123 

Coordination*  of  muscles.  —  Would  you  like  to  see  two 
persons  try  to  thread  a  needle,  one  holding  the  thread  and 
the  other  the  needle?  Would  they  succeed  well?  Or  in 
so  simple  a  matter  as  the  use  of  the  knife  and  fork  in  eating, 
could  it  be  easily  done  if  one  holds  the  piece  of  meat  with  the 
fork  while  the  other  tries  to  cut  it  ?  Why  is  it  that  the  right 
hands  of  two  persons  cannot  work  so  well  together  as  the 
right  and  left  hands  of  one  person?  It  is  because  of  the 
nervous  connection  between  the  hands  of  the  same  person, 
so  that  one  hand  knows  just  what  the  other  is  doing. 

Let  us  think  of  what  takes  place  in  our  bodies  when  we 
throw  a  stone  at  a  mark.  At  the  same  time  we  see  the 
mark,  hold  the  stone  in  the  hand,  and  throw  it.  In  throw- 
ing a  stone,  at  least  a  dozen  muscles  are  used.  Each  one  of 
these  must  contract  at  the  right  time  and  in  the  right  way, 
or  the  stone  will  miss  the  mark.  Each  muscle  shortens 
under  the  influence  of  a  nerve  impulse  brought  from  the 
brain  by  a  motor  nerve.  If  one  muscle  shortens  an  instant 
too  soon,  or  a  little  too  much,  the  stone  goes  to  one  side. 
This  working  together  of  the  muscles  by  the  aid  of  the  nerves 
is  called  coordination.  Coordination  is  necessary,  even  in 
standing  erect. 

Muscular  energy.  —  It  is  well  known  that  the  activities 
upon  which  life  depends  involve  a  continuous  expenditure 
of  energy.  The  beating  of  the  heart,  the  secretion  by  glands, 
the  contraction  of  muscles,  the  discharge  of  nerve  impulses  — 
all  expend  energy.  It  is  also  well  known  that  such  activi- 
ties involve  a  constant  breaking  down  of  chemical  compounds. 
These  compounds  come  from  the  food  eaten  and  they  may 
be  used  at  once  or  after  being  stored  in  the  body.  These  two 
facts  then  are  closely  associated : 

1.  The  constan   breaking  down  of  chemical  compounds. 

2.  The  continuous  expenditure  of  energy. 
Production.  —  But  just  how  is  energy  formed  in  the  body? 

It  is  formed  by  the  chemical  action  of  the  compounds  which 


124  Healthful  Living 

come  from  the  food  we  eat.  All  the  energy  that  is  available 
in  the  muscle  for  contraction  has  its  origin  in  the  chemical 
changes  that  follow  after  the  nerve  impulse  has  come  to  the 
muscle.  We  shall  understand  better  what  energy  is  when 
we  remember  that  heat  and  energy  are  the  same.  The 
physicist  says  that  heat  is  the  lowest  form  of  energy.  The 
chemist  can  show  that  chemical  combinations  liberate  heat, 
which  tends  to  express  itself  as  energy.  Consider  the 
laboratory  experiment  on  page  56.  So  in  the  body,  the 
chemical  union  of  food  elements  produces  energy  which 
appears  in  the  different  cells  in  the  form  which  is  of  use  to 
that  cell.  The  voltaic  cell  is  similar  to  the  nerve  cell  and 
the  electric  current  produced  is  similar  to  the  nerve  impulse 
of  the  nerve  cell.  The  heat  produced  in  the  test  tube  by 
the  action  of  the  zinc  and  sulphuric  acid  represents  the  heat 
produced  in  the  muscle  after  the  chemical  action  of  the  food 
compounds.  What  starts  the  chemical  action  of  the  food 
elements  in  the  muscle  ? 

The  conversion  of  food  into  heat  and  energy  is  going 
on  in  the  body  all  the  time  so  long  as  life  exists.  It  is  less 
in  sleep  and  more  during  activity.  It  is  maintained  by  the 
food  eaten  daily.  Is  this  an  argument  for  nutritious  foods, 
properly  cooked  and  carefully  eaten?  If  no  food  is  eaten, 
it  goes  on  just  the  same  and  uses  up  the  cells  of  the  body. 
How  can  weight  be  reduced?  More  energy  is  required  for 
stout  than  for  thin  persons ;  more  in  cold  weather  than  in 
hot,  more  in  fever  than  in  health.  A  growing  child  requires 
more  energy  in  relation  to  its  weight  than  an  adult.  If  a 
child  weighs  60  pounds  and  a  man  weighs  150  pounds,  which 
will  require  more  energy?  If  the  child  needs  1920  units 
of  heat  and  if  the  man  needs  2850  units  of  heat,  which  re- 
quires more  in  relation  to  its  weight?  The  heat  energy 
necessary  for  muscular  contraction  may  be  obtained  from  any 
of  the  three  foodstuffs — carbohydrates,*  fats,*  or  proteins.* 
It  is  believed  that  the  carbohydrates  afford  the  most  favor- 


The  Muscles  in  Action  and  the  Hygiene  of  Exercise    125 

able  source  of  supply  and  they  will  be  used  first,  if  present 
in  sufficient  amount.  The  blood  in  the  arteries  going  to  the 
muscles  contains  more  sugar  than  the  blood  in  the  veins 
coming  from  the  muscles.  Would  sweet  chocolate  be  a  good 
food  to  carry  on  a  long  tramp  ? 

Expenditure.  —  It  is  found  that  the  use  of  many  small 
muscles  is  much  more  exhausting  than  the  use  of  a  few  larger 
ones.  This  is  on  account  of  the  nerve  energy  consumed. 
A  drummer  beating  a  big  bass  drum  may  do  more  muscular 
work  than  one  who  plays  a  tune  softly  on  the  piano,  but  the 
piano  playing  exhausts  the  performer  much  sooner.  This 
is  because  the  movements  of  the  wrist  and  fingers  employ 
thirty  muscles  and  a  great  number  of  nerves.  The  striking 
of  the  keys  with  the  ends  of  the  fingers,  where  some  of  the 
most  sensitive  nerves  of  the  body  terminate,  may  have  some 
effect  also,  and  may  help  to  explain  why  so  many  persons, 
especially  girls,  who  take  little  other  exercise,  have  become 
nervous  wrecks  from  piano  playing.  Continued  typewriting 
and  penmanship  are  exhausting,  but  typewriting  gives  vari- 
ety of  motion,  while  handwriting  calls  for  a  monotonous  use 
of  the  same  muscles. 

The  fact  that  the  muscles  are  arranged  in  pairs  as  antago- 
nists of  each  other  may  have  a  calamitous  effect  in  the  case 
of  persons  with  ill-regulated  nervous  system.  Such  persons 
on  account  of  anxiety  or  worry,  doubt,  or  over-active  desire, 
keep  their  muscles  drawn  tense,  the  antagonists  pulling 
against  each  other,  and  after  a  while  they  lose  the  power  of 
relaxing  their  muscles.  They  wear  anxious  expressions,  be- 
cause the  muscles  of  the  face  are  never  relaxed  or  in  repose. 
Their  movements  are  nervous  and  jerky  instead  of  graceful 
and  easy.  Their  breathing  is  not  deep  and  natural,  and 
their  voices,  therefore,  are  not  even  and  steady.  They 
cannot  be  perfectly  still,  but  chew  gum  or  a  pencil,  rock  the 
chair,  bite  their  finger  nails,  or  claw  their  knuckles.  Have 
you  any  friends  who  are  handicapped  by  this  condition  of 


126 


Healthful  Living 


over-tension?  When  such  people  listen  to  a  sermon,  their 
backs  get  tired  because  they  cannot  relax  comfortably  in 
the  seat.  When  they  lie  down,  they  try  to  hold  the  body 
on  the  bed,  and  instead  of  relaxing  the  muscles  of  the  neck, 
try  to  hold  the  head  on  the  shoulders. 

Over-tension  is  common  to  adults  in  cold  climates,  but 
it  is  also  known  in  warm  climates.  A  graceful  person,  like 
a  child,  uses  just  the  muscles  necessary  for  any  act,  and  no 
more.  Ease  of  manner,  as  well  as  health,  makes  important 
the  correction  of  conditions  to  which  all  hurrying,  am- 
|  v  bitious  persons  are  liable  in  an 

age  of  keen  competition  and  of 
ambition  for  learning  and  dis- 
tinction. 

Muscular  tone.  —  That  the 
muscles  may  be  always  ready  for 
use,  they  must  not  be  entirely 
soft  and  flabby,  but  should  be 
under  a  condition  of  very  slight 
contraction,  called  tone  (Fig.  93). 
We  find  that  the  muscular  walls 
of  the  blood  vessels  possess  tone. 
It  is  this  condition  of  slight  con- 
traction which  causes  a  wound  in 
the  flesh  to  gape  open.  If  a  ten- 
don is  cut,  the  muscle  shortens 
on  account  of  its  tone.  If  the 
nerve  going  to  the  muscle  is  cut, 
FIG.  93  -  Diagram  of  good  the  muscle  lengthens  a  little,  that 

posture  showing  well-developed     .  .  , 

rectusabdominis  muscle  in  tonic    is,  it  relaxes,  showing  that  there 


Sternum 


Os  Pubis 


contraction ;  dotted  line  show- 
ing poor  posture  with  relaxed 
and  flabby  abdominal  wall. 


mugt   be   f ajnt    but    constant   im- 
.  .  .  •     ,« 

pulses  coming  through  the  nerve 
to  keep  the  muscle  in  tone.    When 

one  is  asleep,  the  body  does  not  lie  perf ectly  straight,  but 
the  joints  are  slightly  bent  to  allow  relaxation. 


The  Muscles  in  Action  and  the  Hygiene  of  Exercise     127 

Muscular  activity  and  fatigue.  —  If  we  suspend  a  frog's 
muscle  from  a  muscle  clamp,  and  attach  the  tendon  to  a 
writing  lever,  on  stimulation  of  the  muscle  by  an  electric 
current  we  can  record  the  contraction  that  results.  In  a 
series  of  contractions  (Fig.  27)  of  a  fresh  muscle,  there  will 
be  seen  a  gradual  increase  in  height  of  the  contractions 
(called,  Die  Treppe  —  the  staircase}  until  the  maximum  is 
reached  (Fig.  27) ;  and  presently  the  height  will  decrease. 
The  height  will  gradually  fall  until  no  contraction  at  all 
occurs,  no  matter  how  strong  the  stimulus.  The  increase 
in  power  at  first  is  due  to  the  increased  irritability  of  the 
muscle  cells  brought  on  by  the  presence  of  chemical  sub- 
stances formed  in  the  muscle  during  the  production  of  energy. 
These  are  known  as  fatigue  substances.  They  are  forms  of 
chemical  compounds  which  represent  the  waste  material 
left  after  the  combustion  in  the  muscle,  and  in  this  re- 
spect resemble  the  ashes  left  in  the  furnace.  After  these 
fatigue  substances  increase  in  amount,  the  irritability  of 
the  muscle  is  lessened,  so  that  there  is  a  decrease  in  the 
height  of  the  contractions  (Fig.  27).  What  purpose  do 
warming-up  exercises  have  in  relation-  to  performing  an 
athletic  feat? 

When  fat  or  carbohydrate  is  used  as  the  source  of  energy 
for  muscular  contractions,  the  waste  products  are  carbon 
dioxide,  mono-potassium  phosphate,  and  lactic  acid.  When 
proteins*  are  used  as  energy,  the  waste  products  from  these 
are  in  the  forms  of  urea  uric  acid,  creatin,  and  others.  Now, 
all  these  substances  interfere  with  the  working  of  the  muscle. 
By  getting  into  the  blood  stream  and  by  being  carried  to 
other  parts  of  the  body,  the  effects  from  a  local  activity 
may  be  felt  all  over  the  body.  Fatigue  of  one  part  lowers 
the  efficiency  of  the  rest  of  the  body.  These  fatigue  products 
are  removed  chiefly  by  the  kidneys  and  lungs.  Rest,  sleep, 
and  food  to  restore  the  chemical  forces  used  are  necessary 
for  complete  recuperation  of  the  body  after  a  fatiguing  task. 


128 


Healthful  Living 


Sleeping  is  the  best  way  of  resting.     What  are  the  other 
lines  in  this  quotation? 

"  Sleep  that  knits  up  the  ravell'd  sleave  of  care." 
Who  wrote  these  lines?  Did  he  know  much  about  physi- 
ology? Is  such  knowledge  of  value  to  a  poet  and  a  writer? 
Name  the  professions  in  which  knowledge  of  physiology  is 
absolutely  necessary.  Is  it  of  value  to  a  father?'  To  a 
mother  ? 

In  Figure  94  two  graphic*  representations  of  muscular 
contractions  are  shown.     In  A  the  contractions  at  the  be- 


FIG.  94.  —  The  effect  of  rest  on  muscular  contractions.  A  shows  the 
contractions  of  a  fresh  muscle.  B  shows  the  contractions  of  the  same 
muscle  with  a  rest  of  five  minutes  after  doing  the  work  shown  in  A. 

ginning  are  higher  than  those  in  B.  Between  A  and  B  there 
was  a  rest  of  5  minutes.  It  is  to  be  noticed  that  the  con- 
tractions in  B  at  the  beginning  are  higher  than  those  at  the 
ending  of  A,  but  not  as  high  as  those  at  the  beginning  of  A  ; 
in  addition  it  is  seen  that  fatigue  comes  quicker  in  B  than  in 
A.  These  contractions  are  of  the  muscle  that  abducts  the 
index  finger. 

The  effects  of  stimulants  and  narcotics  *  on  muscular  ac- 
tion. —  The  weaker  forms  of  alcohol,  such  as  ale  and  beer, 
cause  a  change  into  fat  of  much  of  the  albumin*  in  muscle 
cells,  thus  bringing  about  a  bloated  and  flabby  condition, 
called  fatty  degeneration.*  It  may  even  reach  the  heart, 


The  Muscles  in  Action  and  the  Hygiene  of  Exercise    129 

causing  a  dangerous  disease  called  fatty  degeneration  of 
the  heart.  There  are  other  causes  of  this  condition.  If 
an  athlete  who  has  developed  enormous  muscles  suddenly 
ceases  to  train,  his  muscles  may  undergo  fatty  degeneration. 
Through  the  narcotic  or  deadening  effect  of  alcohol,  the 
nerves  become  less  sensitive,  and  fatigue  is  not  so  readily 
perceived.  This  unawareness  of  the  real  bodily  condition 
gives  the  drinker  a  deceptive  feeling  of  strength  and  power. 

It  has  been  found  that  two  hours  after  taking  two  ounces 
of  whisky  mixed  with  eight  ounces  of  water,  the  muscular 
strength  of  the  man  experimented  on  was  reduced  one  third. 
This  means  that  a  lifting  power  of  three  hundred  pounds  was 
reduced  to  two  hundred  pounds.  An  old  drunkard  usually 
has  a  dragging  gait  and  trembling  hands.  Coffee,  which  is  a 
stimulant,  sometimes  causes  a  twitching  of  the  eyelids ;  this 
is  a  sign  that  the  body  is  being  irritated. 

The  effect  of  exercise  on  growth.  —  Exercise  has  a  stimu- 
lating effect  upon  growth.  This  effect  has  been  recorded 
many  times  by  scientific  observers.  Henry  G.  Beyer,  M.D., 
reported  observations  on  the  growth  of  188  naval  cadets  who 
took  special  systematic  exercise,  and  compared  it  with  the 
usual  growth  of  cadets  of  the  same  age. 

There  was  an  increase  in  height  of  more  than  one  inch 
above  that  which  took  place  without  the  special  exercise. 

The  increase  in  strength  was  five  times  as  much  as  the 
normal  increase. 

There  was  an  increase  in  weight  of  77  pounds  in  the  four 
years  during  which  the  observations  were  made. 

There  was  an  increase  in  lung  capacity  *  of  1.72  liters. 

The  growth  of  the  body  in  height  and  weight  is  determined 
partly  by  the  influence  of  heredity  and  partly  by  the  kind 
of  care  the  body  receives.  Height  is  determined  largely  by 
heredity,  and  weight  largely  by  environment.  The  following 
table  by  Dr.  Holt  shows  the  weight,  height,  and  circumfer- 
ence of  the  head  and  chest  from  birth  to  the  sixteenth  year : 


130 


Healthful  Living 


AGE 

WEIGHT  IN 
POUNDS 

HEIGHT  IN 
INCHES 

CHEST  IN 
INCHES 

HEAD  IN 
INCHES 

Birth 

Boys 

7.55 

20.6 

13.4 

13.9 

Birth 

Girls 

7.16 

20.5 

13.0 

13.5 

6  months 

Boys 

16.0 

25.4 

16.5 

17.0 

6  months 

Girls 

15.5 

25.0 

16.1 

16.6 

12  months 

Boys 

20.5 

29.0 

18.0 

18.0 

12  months 

Girls 

19.8 

28.7 

17.4 

17.6 

18  months 

Boys 

22.8 

30.0 

18.5 

18.5 

18  months 

Girls 

22.0 

29.7 

18.0 

18.0 

2  years 

Boys 

26.5 

32.5 

19.8 

18.9 

2  years 

Girls 

25.5 

32.5 

18.5 

18.6 

3  years 

Boys 

31.2 

35.0 

20.1 

19.3 

3  years 

Girls 

30.0 

35.0 

19.0 

19.0 

4  years 

Boys 

35.0 

38.0 

20.7 

19.7 

4  years 

Girls 

34.0 

38.0 

20.5 

19.5 

5  years 

Boys 

41.2 

41.7 

21.5 

20.5 

5  years 

Girls 

39.8 

41.4 

21.0 

20.2 

6  years 

Boys 

45.1 

44.1 

23.2 

6  years 

Girls 

43.8 

43.6 

22.8 

7  years 

Boys 

49.5 

46.2 

23.7 

7  years 

Girls 

48.0 

45.9 

23.3 

8  years 

Boys 

54.5 

48.2 

24.4 

8  years 

Girls 

52.9 

48.0 

23.8 

9  years 

Boys 

60.3 

50.1 

25.1 

9  years 

Girls 

57.5 

49.6 

24.5 

10  years 

Boys 

66.6 

52.2 

25.8 

21.0 

10  years 

Girls 

64.1 

51.8 

24.7 

20.7 

11  years 

Boys 

72.4 

54.0 

26.4 

11  years 

Girls 

70.5 

53.8 

25.8 

12  years 

Boys 

79.8 

55.8 

27.0 

12  years 

Girls 

81.5 

55.1 

26.8 

13  years 

Boys 

88.3 

58.2 

27.7 

13  years 

Girls 

91.2 

57.7 

28.0 

14  years 

Boys 

99.3 

61.0 

28.8 

14  years 

Girls 

100.3 

60.3 

29.2 

15  years 

Boys 

110.8 

63.0 

30.0 

21.8 

15  years 

Girls 

106.4 

61.4 

30.0 

21.5 

16  years 

Boys 

123.7 

65.6 

31.2 

16  years 

Girls 

118.0 

61.7 

30.8 

The  relation  of   exercise  to  health.  —  It  was  learned  on 
page  6  that  the  muscular  system  developed  to  make  loco- 


The  Muscles  in  Action  and  the  Hygiene  of  Exercise     131 

motion  possible.  Animals  of  every  species  are  dependent 
upon  movement  for  obtaining  the  necessities  of  life.  The 
important  thing  for  us  to  remember  is  that  for  innu- 
merable years  muscles  have  been  a  part  of  the  human  body 
as  constructed  to-day.  We  have  inherited,  therefore,  a 
muscular  system,  and  with  that  system  we  have  inherited 
the  need  for  activity.  Young  people  are  usually  very  active, 
but  too  often,  after  school  days,  they  lead  physically  inactive 
lives  in  office,  store,  or  home.  Some  people  think  they  can 
maintain  health  and  strength  by  a  two-minute  drill  in  their 
room  before  retiring.  Health  cannot  be  obtained  or  main- 
tained by  such  condensed  pill-like  measures.  There  must 
be  outdoor  life  and  outdoor  exercise  if  the  human  body  is 
to  keep  its  inheritance.  The  boy  and  girl  in  school  and 
college  should  learn  to  enjoy  and  to  become  proficient  in 
some  game  or  sport,  so  that  in  adult  life  this  activity  may 
be  followed.  Too  often  in  adult  life  men  and  women  are 
so  weak  physically  that  they  do  not  enjoy  exercise.  Such 
condition  of  the  body  is  unfavorable  to  the  maintenance  of 
health,  to  say  nothing  of  the  resulting  effect  of  bad  disposi- 
tion, ill  temper,  and  nervousness.  Walking  for  some  people 
is  a  serious  task.  If  there  is  proper  training  throughout 
life,  walking  may  be  mora  than  a  means  of  progression  — 
it  may  be  a  real  joy. 

There  are  those  who  go  to  the  other  extreme  as  regards  ex- 
ercise. They  strive  constantly  for  records  in  athletic  events. 
They  over-develop  their  hearts,  and  serious  harm  often  re- 
sults. The  danger  for  the  nation,  however,  is  not  from  ath- 
letics, but  rather  from  a  lack  of  all  forms  of  physical  educa- 
tion. It  is  to  be  remembered,  therefore,  that  exercise  is 
important,  not  only  for  the  health  of  the  individual,  but  also 
for  the  strength  and  vigor  of  the  race.  We  have  received 
our  bodies  as  an  inheritance  from  an  ancestry  that  lived 
largely  an  outdoor  life.  To-day  there  is  a  great  concen- 
tration of  population  in  cities,  and  it  is  necessary  that  city 


132 


Healthful  Living 


folk  exercise  out-of-doors  to  preserve  the  inheritance  that 
has  been  received. 

Forms  of  exercise.  —  It  is  best  to  choose  a  form  of  exercise 
that  you  enjoy.  Exercise  that  is  performed  as  a  task  is  a 
drain  on  the  nervous  system;  its  results  are  questionable, 
and  sooner  or  later  it  is  given  up  in  disgust.  Too  often  the 


FIG.  95.  —  Which  is  the  better  —  forced  exercise  or  games? 

expression  is  heard,  "  I  hate  gymnasium  work."  This 
comes  because  the  exercise  is  not  interesting  and  in  no  way 
appeals  to  the  instincts  of  the  child.  Most  games  and 
sports  are  excellent  forms  of  exercise  (Fig.  95) . 

The  games  that  are  most  interesting  are  those  that  have 
the  "  give-and-take  "  principle  present.  Such  games  give 
to  the  player  an  opportunity  and  in  turn  take  a  chance. 


The  Muscles  in  Action  and  the  Hygiene  of  Exercise     133 

This  is  illustrated  in  such  a  game  as  baseball.  The  pitcher 
gives  the  batter  a  chance  at  the  ball  and  the  batter  takes 
the  opportunity  offered,  or  refuses  it.  Such  games  as  swing- 
ing are  less  interesting  because  they  have  not  this  principle 
present.  In  which  of  the  following  games  is  this  "  give-and- 
take  "  element  present  and  in  which  is  it  most  prominent? 

Tennis  is  a  splendid  game.  It  may  be  played  in  youth 
and  in  adult  life  by  both  sexes.  It  has  a  fine  play  element 
and  gives  good  physiological  results  on  the  body. 

Swimming  is  a  very  desirable  form  of  exercise.  Every 
city  should  have  swimming  pools,  so  that  the  sport  may  be 
practiced  in  winter  as  well  as  in  summer.  Sea  bathing  is 
very  beneficial.  To  what  is  the  beneficial  effect  chiefly  due  ? 


FIG.  96.  —  Cabin  built  by  scouts  for  use  as  Troop  Heauquarters. 

Camping.  —  The  outdoor  activities  of  the  Boy  Scouts, 
Girl  Scouts,  Camp  Fire  Girls,  and  other  camping  organiza- 
tions afford  a  fine  opportunity  for  outdoor  exercise  (Fig.  96). 


134  Healthful  Living 

The  activities  out-of-doors  are  especially  beneficial  upon 

\  the  blood.     For  several  years  the  author  has  kept  a  record 

\of  the  increase  in  the  iron  content  of  the  blood  in  girls  in  a 

jsummer  camp.     After  six  weeks  of  camping  at  Camp  Mesa- 

cosa  the  average  increase  in  hemoglobin  has  been  16  per 

cent.     Some  girls  gained  as  much  as  22  per  cent.     Good 

food,  exercise,  sleep  and  the  sun's  rays  are  the  important 

factors  in  promoting  this  improved  blood  condition. 

Walking  and  running,  if  not  done  too  leisurely,  are  good 
exercises.  Americans  probably  make  too  great  a  use  of 
street  cars.  English  women  are  noted  as  walkers,  and  in 
the  cooler  parts  of  the  United  States  this  custom  would  be 
equally  effective  in  preventing  nervousness  and  weakness 
among  women.  Walking  requires  proper  shoes. 

Running  is  a  still  better  exercise,  but  it  should  be  begun 
gradually  and  with  caution,  so  as  to  give  heart  and  lungs 
opportunity  to  become  strong  enough  to  sustain  the  in- 
creased effort  required  of  them.  One  should  never  run 
with  the  mouth  open.  One  should  keep  in  such  physical 
condition  as  at  all  times  to  be  able  to  run  swiftly  and  effi- 
ciently. Too  frequently  persons  allow  themselves  to  become 
so  unfit  that  a  run  for  100  yards  is  impossible.  To  keep 
" fit"  is  at  times  difficult ;  it  is  always  worth  the  effort. 

Boxing  and  wrestling  and  fencing  are  good  sports,  but  they 
are  not  common  because  of  the  skill  necessary  for  their  per- 
formance. They  are  more  liable  to  produce  injury  of  the 
participants  and  so  should  be  well  supervised.  Boxing  has 
become  very  popular  in  the  training  of  the  American  army 
for  the  Great  War.  It  provides  not  only  the  general  bene- 
ficial effects  of  exercise,  but  the  movements  are  similar  in 
type  and  quality  to  the  movements  used  in  fighting  with  the 
bayonet.  Every  boy  should  develop  skill  in  at  least  one 
of  these  three  sports. 

The  group  games  such  as  volley  ball,  dodge  ball,  captain 
ball,  and  the  group  relays  such  as  all-up  relay,  overhead 


The  Muscles  in  Action  and  the  Hygiene  of  Exercise    135 

pass  relay,  and  others  are  splendid  games  for  the  school 
ground  and  gymnasium  (Fig.  97).  The  tug-of-war  is 
excellent  exercise  (Fig.  98). 


FIG.  97.  —  The  relay  race  provides  competition  and  demands  cooperation. 
Notice  the  starting  position  of  the  girl  on  the  right.  Girls  may  learn  to 
run  freely  as  boys  do. 

The  specialized  games,  such  as  baseball,  basketball,  and  foot- 
ball are  admirable   during  school   days,    but   they   are  of 


FIG   98.  —  Blind  boys  in  a  tug  of  war.     Games  and  contests  out  of 
doors  are  available  for  all  —  even  the  blind. 

little  use  after  school  days  are  over.     Such  games  not  only 
strengthen  muscle  and  nerve  but  also  may  develop  presence 


Healthful  Living 


of  mind,  coolness,  fearlessness,  self-control,  and  other  fine 
qualities.      Basketball  with  girls'  rules,   and    indoor  base- 


FIG.  99.  —  Hockey  requires  strength  and  is  valuable  for  the  High 
School  girl. 

ball  using  the  number  12  playground  ball,  are  fine  games 
for  girls  in  high  school  and  college. 


FIG.  100.  —  A  Morris  Dance.  Men  and  boys  do  some  dances  better  than 
women  and  girls.  Dances  of  this  type  out  of  doors  are  not  only  healthful 
but  also  "fun  to  do."  This  kind  of  dancing  calls  for  strength  and  endurance 
and  may  enlist  the  strongest  athlete. 

Hockey  is  a  splendid  game  for  girls.     The  field  should  be 
shortened  to  70  yards,  because  the  regulation  field  makes 


The  Muscles  in  Action  and  the  Hygiene  of  Exercise     137 

too  strenuous  a  game  for  girls,  and,  moreover,  the  shorter 
field  permits  more  scoring  and  thus  adds  to  the  interest  of 
the  game. 

Dancing.  —  The  dance  at  one  time  was  a  ritual  used 
in  religious  ceremonies.  Dancing,  therefore,  really  began  as 
a  religious  cult.  To-day  there  are  different  forms  of  danc- 


FIG.  101.  —  Throwing  the  discus.     The  group  in  the  background  is 
holding  a  group  baseball  throw. 

ing.  Folk*  dances  are  the  dances  of  folk  people  giving  ex- 
pression to  their  feelings.  These  are  dances,  therefore,  that 
are  characteristic  of  the  nations,  and  in  this  way  we  must 
think  of  the  Tarantella  of  Spain,  the  Irish  Lilt  of  Ireland 
and  the  English  Country  Dances.  ^Esthetic  *  dancing  is  an 
attempt  to  produce  certain  graceful  forms  of  movement  in 
dance.  Too  frequently,  it  is  taught  as  a  series  of  steps  or 
poses  in  which  there  is  no  thought  or  emotion.  It  thus 
becomes  a  mere  exercise.  It  should  be  taught  as  an  art 


138 


Healthful  Living 


in  which  all  the  technique  serves  as  the  medium  for  the  self- 
expression  of  the  dancer.  Social  dancing  is  in  common  use 
in  the  United  States  and  eastern  Europe.  It  is  exhilarating 
and  restful  on  account  of  the  music  and  the  rhythm.  If  it  is 
done  finely,  in  a  beautiful  way,  it  is  very  beneficial. 

Athletic  sports  for  girls  need  to  have  standards  that  are 
not  too  difficult 'for  the  girl  athlete.  Girls  should  not  try 
to  do  the  same  events  in  which  boys  excel.  There  are,  how- 


FIG.  102.  —  Throwing  the  lariat.     This  event  calls  for  accurate  judgment 
and  good  body. 

ever,  some  athletic  events  that  girls  do  very  well,  and  two  of 
these  are  shown  in  Figures  101,  102.  In  the  figures  showing 
the  discus  and  lariat,  notice  that  the  left  foot  of  the  athlete 
is  forward  and  the  right  arm.  This  opposite  position  of  the 
arm  and  leg  is  very  important  in  all  throwing  movements. 
For  example,  in  throwing  a  baseball  with  the  right  arm,  the 
left  foot  should  be  forward.  Girls  are  familiar  with  this  law 
in  dancing,  but  because  of  their  lack  of  training  in  sports 


The  Muscles  in  Action  and  the  Hygiene  of  Exercise    139 

they  rarely  show  the  good  position  of  the  discus  thrower 
(Fig.  101).  Camping  with  its  related  activities  is  very  valu- 
able for  girls  (Fig.  103).  The  following  health  essentials  for 


r 


FIG.   103.  —  City  girls  on  a  "hike"  in  the  country.     Which  one  of  the 
three  girls  shows  the  best  posture? 

girls  12  to  14  years  old  are  good  rules  for  all  girls.  The  girl 
athlete  could  follow  no  better  training  schedule  than  this 
one,  proposed  by  Dr.  Thomas  D.  Wood. 

SUGGESTED  ESSENTIALS  FOR  HEALTH  OF  GIRLS  12  TO  14  YEARS  OLD 

1.  Sleep.  —  10|  hours  in  bed  each  night. 

2.  Food.  —  A  nutritious  diet  with  special  emphasis  upon  an 
adequate  breakfast. 

3.  Play  and  recreation.  —  At  least  one  hour  of  out-door  ac- 
tivity each  day,  during  full  daylight. 

4.  Bathing.  —  A  tepid  to  cool  sponge,  shower,  or  quick  plunge 
in  the  tub  daily,  before  breakfast. 

5.  All  the  out-door  air  possible,  particularly  in  the  sleeping 
room. 

6.  Freedom  from  worry,  hurry,  and  over-excitement. 

The  above  schedule  may  serve  with  slight  alteration  as 
" training  rules"  for  boys.  The  boy  who  is  interested  in 
athletics  and  physical  efficiency  will  not  use  tobacco.  More- 


140  Healthful  Living 

over,  he  should  not  spend  more  than  three  hours  a  day  in 
practice.  For  many  of  the  track  sports,  a  half  hour  is 
sufficient.  The  high  school  boy  is  frequently  injured  in 
athletics  by  engaging  in  too  many  events  in  track  meets, 
so  that  later,  in  college,  he  has  not  the  endurance  that  he 
needs  for  sharper  competition. 

Over-development  of  muscles.  —  As  important  as  mus- 
cular exercise  is  for  sending  the  blood  bounding  through  the 
veins  and  renewing  the  health  of  every  part,  exercise  can  be 
overdone.  Some  athletes  develop  great  heavy  muscles 
which  are  a  burden  to  the  vital  organs  to  support.  They 
do  not  take  care  to  develop  their  lungs  and  breathing  powers 
in  proportion.  Breathing  exercises  are  often  used  to  over- 
come the  bad  effects  of  inactivity  and  torpor.  This  method 
of  getting  strength  and  vigor  is  wrong.  Exercise,  vigorous 
enough  to  increase  the  respiration,  should  be  used,  and  the 
breathing  will  care  for  itself.  Those  who  aim  only  to  de- 
velop certain  muscles,  who  do  nothing  but  apparatus  work 
or  some  such  specialty,  get  large  muscles  but  not  health  and 
strength  of  body.  Such  athletes  die  young.  Among  those 
who  have  succumbed  to  consumption  may  be  mentioned 
Kehoe,  the  famous  club  swinger;  Dowd,  the  teacher  of 
physical  culture ;  "  Jap,"  the  wrestler ;  Winship,  the  in- 
ventor of  the  health  lift ;  Kennedy,  the  strong  man ;  and 
Peter  Jackson,  the  pugilist.  Complete  living  with  conditions 
of  health  and  activity  for  all  the  organs,  without  extreme 
use  of  any  of  them,  is  most  conducive  to  a  long  and  healthful 
life. 

APPLIED   PHYSIOLOGY 
Exercise  I 

1.  Does  a  few  minutes'   practice  in  a  gymnasium   suffice  for 
a  day's  exercise  ? 

2.  Is  there  any  relation  between  the  amount  of  bodily  exer- 
tion necessary  for  a  person's  health  and  the  amount  of  wealth  lie 
possesses  ? 


The  Muscles  in  Action  and  the  Hygiene  of  Exercise     141 

3.  It  is  said  that  an  Indian  often  runs  or  trots  sixty  miles  per 
day,  and  that  he  rests  his  muscles  without  stopping  by  running  for 
a  while  chiefly  with  the  hip  joint  and  muscles  of  the  thigh,  then 
with  the  knee  joint  and  muscles  of  the  upper  leg.     Can  you  rest 
some  of  the  running  muscles  while  running? 

4.  Can  you  relax  the  chewing  muscles  so  that  the  lower  jaw  will 
swing  loosely  when  the  head  is  shaken  ? 

5.  Can  you  relax  the  muscles  of  the  forearm  so  that  the  hand 
will  shake  loosely  on  the  wrist  and  the  fingers  in  their  sockets  ? 

6.  Can  you  relax  the  whole  arm  so  that  another  person  can 
move  it  as  a  flexible  rope? 

7.  Which  joints  of  the  limbs  lock  and  refuse  to  bend  further 
when  the  limb  is  straightened? 

8.  Which  muscles  have  become  useless  with  most  persons, 
although  some  can  still  use  them  ? 

9.  The  average  man  has  60  Ibs.  of  muscle  and  2  Ibs.  of  brain ; 
one  half  of  the  blood  goes  through  the  muscles  and  one  fifth  goes 
through  the  brain.     What  inference  may  you  draw  as  to  the  kind 
of  life  we  should  lead  ? 

10.  What  are  the  beneficial  effects  of  exercise  upon  the  func- 
tions of  the  skin? 

11.  Is  a  slow  formal  walk  suitable  exercise?     What  exercise 
do  you  enjoy  most  ?     Do  you  practice  it  ? 

Exercise  II 

12.  How  can  we  best  prove  that  we  have  admiration  and  respect 
for  our  wonderful  bodies  ? 

13.  In  what  part  of  the  skeleton  is  it  most  important  to  keep 
the  muscular  walls  firm  and  strong  in  order  to  hold  the  internal 
organs  in  position  ? 

14.  Why  should  a  youth  who  wishes  to  excel  in  athletic  con- 
tests abstain  from  the  use  of  tobacco  ? 

15.  How  does  the  fact  that  if  the  nerves  of  one  side  of  the  face 
are  paralyzed  the  face  will  be  drawn  toward  the  other,  illustrate 
muscular  tone? 

16.  Why  does  a  game  of  baseball  on  Saturday  afternoon  ac- 
tually rest  a  tired  shop  boy? 

17.  What  movements  did  you  ever  see  a  cat  go  through  for 
the  sake  of  exercise? 

18.  What  animals  have  you  ever  seen  play?     Stretch  them- 
selves for  exercise  ? 


142 


Healthful  Living 


19.  Why  do  you  feel  so  exhausted  after  a  fright  ? 

20.  How  do  you  account  for  the  origin  of  the  mental  state, 
which  holds  in  practice  if  not  in  theory,  that  all  physical  labor 
is  an  unmitigated  evil  ? 

21.  Do  you  know  persons  who  seem  to  be  possessed  by  what  is 
called  "  the  spirit  of  jerkiness  "  ?     How  could  they  overcome  it? 

22.  What  is  energy?     How  is  it  formed? 


LABORATORY  EXERCISES 

Experiment  1.    To  study  the  contraction  of  muscle. 

Material!  —  Muscle  from  a  frog,  muscle  clamp,   inductorium 
(Fig.  187),  pincers,  acetic  acid. 
Method  and  observation. 

(a)  Arrange  the  muscle  from  the  frog's  leg  on  a  muscle  clamp 
and  keep  the  nerve  intact.     Pinch  the  end  of  the  nerve  and  ob- 
serve what  happens 
to  the  muscle. 

(6)  Touch  the 
nerve  with  filter 
paper  wet  with  the 
acetic  acid.  What 
happens  ? 

(c)  Place  the  elec- 
trodes of  the  induc- 
torium on  the  nerve 
and  stimulate  with  a 
"break"  shock.  (A 
break  shock  is  pro- 
duced when  the  cir- 
cuit is  broken  by 
raising  the  key. ) 
What  happens  when 
the  nerve  is  stimu- 
lated? 

Experiment  2.    To  study  the  effect  of  cold  and  heat  on  muscular 
contraction. 

Material.  —  Hand    dynamometer     (this    instrument    may    be 
borrowed  from  the  physical  education  teacher),  ice,  and  a  large 


FIG.  104.  —  The  ergograph  ;  about  one  fifth 
the  actual  size. 


1  Apparatus  for  experiments  in  physiology  may  be  obtained  from  the 
Barvard  Apparatus  Co.,  Back  Bay  station,  Boston,  Mass. 


The  Muscles  in  Action  and  the  Hygiene  of  Exercise     143 


This 
three 


Method  and  observation.  — 

(a)  Cool  the  hand  and  arm  up  to  the  elbow  in  ice  water, 
will  cool  the  muscles  which  control  the  fingers.  Make  in 
trials  the  maximal  contraction  on  the  dynamometer. 

(6)  Warm  the  hand  and  arm  with  heat  and  massage,  and  again 
make  three  trials  on  the  dynamometer. 

(c)   Compare  the  results  in  (a)  and  (6).     What  do  these  results 
suggest  for  athletic  activities  and  work  in  the  gymnasium  ? 
Experiment  3.    To  study  the  effect 
of  exercise  on  size  of  muscle. 

Material.  —  A  non-stretchable  and 
non-shrinkable  tape. 

Method  and  observation.  —  Measure 
the  circumference  (girth)  of  the  biceps 
and  triceps  in  the  largest  part  of  the 
upper  arm.  Write  this  measurement 
in  your  book  and  record  the  date. 
For  a  period  of  one  month  daily  ex- 
ercise the  arm  with  dumbbells,  chin- 
ning, or  some  other  exercise  which 
the  physical  education  director  will 
show  you  and  again  measure  the  arm 
in  the  largest  part.  How  much  has 
it  increased  in  size  ? 

Have  the  class  tabulate  on  the 
board  the  gain  and  indicate  the  type 
of  exercise  chosen. 

Experiment  4.    To  study  the  effect  of 
exercise  on  secretion  of  sweat. 

(a)  Swing  Indian  clubs  for  five 
minutes  and  note  whether  perspira- 
tion comes  out  on  the  face  or  body. 

(6)  After  resting  "  run  in  place  " 
for   the    same    length    of    time    and 
notice  whether  there  is  visible  per- 
spiration   on    the    face    or    body, 
difference  ? 
Experiment  5.    To  study  muscular  contraction  and  fatigue. 

Material.  —  Ergograph  (Fig.  104). 

Method  and  observation.  —  Clamp  the  iron  angle  to  a  table 
(Fig.  104)  and  fasten  the  second,  third,  and  fourth  fingers  to  the 
wooden  support.  Upon  the  index  finger,  adjust  the  rod  as  shown 


FIG.  105.  —  The  kymograph 
and  its  aluminium  drum  ;  about 
one  fifth  the  actual  size. 


Why    should    there    be    this 


144  Healthful  Living 

in  the  picture.  Record  the  movement  of  the  rod  on  a  kymograph 
(Fig.  105).  A  highly  glazed  paper,  smoked  by  a  flame,  is  pasted  on 
the  drum  to  receive  the  tracing. 

Does  fatigue  occur?  To  what  is  that  due?  Try  the  experiment 
after  the  day's  work  in  school  and  before  beginning  the  day.  Do 
you  notice  any  difference  ? 


GLOSSARY 

^Esthetic  dancing.  —  A  form  of  dancing  that  attempts  to  produce 
beautiful  poses  and  movements.  The  movements  are  denned 
and  exact  and  are  supposed  to  cultivate  grace  and  harmony 
in  action. 

Albumin.  —  A  transparent,  nitrogen-containing  substance  found  in 
the  blood  and  in  many  animal  and  vegetable  juices  and  solids. 
It  is  a  chief  constituent  of  muscle.  It  has  the  very  complex 
chemical  formula  (C72Hii2Ni8SO22)  . 

Carbohydrate.  —  One  of  a  group  of  chemical  compounds  con- 
taining carbon  combined  with  oxygen  and  hydrogen  in  a 
definite  way.  The  carbohydrates  include  the  group  of  sugars 
represented  by  glucose  (CeH^Oe),  the  double  sugars,  such  as 
cane  (Ci2H220n),  and  the  starches,  which  are  the  simple  sugars 
combined  in  large  chemical  masses  (CeHioOs),,. 

CoSrdination.  —  The  act  of  harmonious  motion  so  that  parts  are 
related  to  produce  movements  or  actions  that  are  not  an- 
tagonistic. 

Die  Treppe.  —  A  German  word  meaning  the  staircase.  Used  to 
describe  the  stairlike  appearance  of  the  graph  made  by  a 
muscle  when  its  contractions  are  recorded. 

Dynamometer.  —  An  instrument  for  measuring  force  or  power 
exerted  by  the  muscles  in  doing  work. 

Fat.  —  A  greasy,  easily  melted,  and  soluble  compound,  forming 
a  part  of  animal  tissue  and  also  found  in  plants.  Fats  consist  of 
fatty  acids  such  as  palmitic,  stearic,  oleic,  butyric,  in  combina- 
tion with  glycerin.  The  formula  of  butter,  a  common  fat,  is 


Fatty  degeneration.  —  Cells  of  the  body,  especially  muscle  cells, 
may  undergo  degeneration.  In  the  process,  the  characteristic 
structure  of  the  cell  is  destroyed,  and  fat  globules  become 
deposited  in  the  cell.  Such  a  change  in  muscle  is  serious,  be- 
cause fat  cannot  do  the  work  of  the  contractile  fibers  formerly 
present  in  the  cell. 


The  Muscles  in  Action  and  the  Hygiene  of  Exercise     145 

Folk  dances.  —  Dancing  that  has  been  derived  from  the  peasants 
of  a  nation,  as  a  rule.  The  folk  dance  arose  in  a  spontaneous 
way  in  an  effort  of  the  people  to  express  their  thoughts,  feel- 
ings, and  emotions. 

Graphic  representation.  —  To  represent  by  writing,  or  recording. 

Lung  capacity.  —  The  amount  of  air  that  can  be  breathed  in  by 
the  greatest  possible  inspiration  after  the  greatest  possible 
expiration.  It  is  measured  by  an  instrument  called  the 
spirometer. 

Narcotic.  —  A  substance  that  produces  depression  of  activity  in 
the  body.  In  large  doses  it  may  produce  stupor  and  even 
death. 

Protein.  —  A  highly  complex  chemical  compound  containing 
carbon,  hydrogen,  oxygen,  nitrogen,  and  often  sulphur.  It 
contains  nitrogen,  and  so  differs  from  fat  and  carbohydrate. 

Psycho-motor.  —  A  term  that  expresses  the  functioning  of  the 
neuro-muscular  mechanism. 

Voltaic  cell.  —  A  jar  containing  a  liquid  in  which  two  metals  are 
immersed  and  capable  of  producing  electricity  through  chem- 
ical action. 


CHAPTER  IX 
FOOD   AND   ITS   ELEMENTS 

I.   Nutritive  and  Non-nutritive  Elements  in  Food. 
Protein 

Carbohydrates 
Fats 
Water 

Mineral  matter 
Table  of  food  elements 
II.    Composition  of  Foods. 

III.  Sources  of  Food  Elements. 

Protein 
Fats  and  oils 
Carbohydrates 

IV.  Uses  of  Food  in  the  Body. 

V.    Proportion  of  Food  Elements  in  a  Normal  Diet. 
VI.   Calculation  of  Food  Values. 
VII.    The  Diet  of  Different  Peoples. 

VIII.    The  Body's  Method  of  Regulating  the  Food  Supply. 
IX.   The  Work  of  Enzymes  in  Digestion. 
Examples  of  enzyme  action 
Classification  of  enzymes 


Nutritive  and  non-nutritive  elements  in  food.  —  The  food 
material  used  by  man  may  be  grouped  under  two  heads, 
nutritive*  and  non-nutritive  constituents.  Nutritive  ele- 
ments are  substances  capable  of  combustion  and  the  pro- 
duction of  energy.  Now,  there  are  certain  salts  whose 
presence  is  necessary  for  life,  but  since  they  are  not  burned, 
they  will  be  classed  as  non-nutritive.  The  nutritive  sub- 
stances are:  (1)  protein,1  (2)  fat,  and  (3)  carbohydrate; 

1  The  attempt  a  few  years  ago  to  secure  the  use  of  the  German  word 
"Proteid"  for  the  nitrogen-containing  foods  was  not  successful,  due  largely 

146 


Food  and  its  Elements  147 

the  non-nutritive  are  (1)  water,  (2)  mineral  matter,  and 
(3)  waste,  such  as  bones,  stones  of  fruit,  cellulose. 

Protein.  —  Protein  is  formed  by  living  matter ;  it  always 
contains  nitrogen.  There  are  definite  proteins,  such  as 
albumin,  haemoglobin,*  globulin,*  etc.  Protein  is  the  great 
tissue-building  material  and  consequently  is  very  important 
in  the  diet  during  the  period  of  growth. 

Carbohydrates.  (Sugars  and  starches.)  —  Why  are  roast- 
ing-ears  sweet,  although  mature  corn  is  not?  It  is  because 
the  sugar  in  the  former  has  been  changed  to  starch  in  the 
latter.  On  the  other  hand,  ripe  apples  are  sweet  because 
the  starch  present  when  the  apple  is  green  has  been  changed 
to  sugar.  Starch  and  sugar  are  so  nearly  alike  in  composi- 
tion and  change  so  readily  into  each  other,  that  as  foods 
they  are  classed  together. 

The  carbohydrates  include  sugars,  starches,  and  gums, 
and  form  the  principal  element  in  vegetables.  They  are 
found  in  vegetables,  nuts,  fruits,  grains,  milk,  and,  to  a 
slight  extent,  in  meat  and  fish. 

Fats.  —  The  fats  come  from  both  animal  and  vegetable 
sources.  Butter,  cream,  fat  of  meat,  olive  oil,  and  nuts 
provide  the  main  supply  of  fat. 

Water.  —  Water  plays  a  very  important  part  in  the  body 
by  affording  a  medium  for  solution  of  the  food  elements 
after  and  during  the  digestive  process. 

Mineral  matter.  —  There  are  in  some  proteins  mineral  ele- 
ments in  chemical  combination.  This  does  not  prevent 
the  classification  of  these  as  proteins,  and  in  such  cases  the 
salt  present  may  play  an  important  part  in  combustion. 

to  the  work  of  Halliburton  and  Hopkins.  These  physiologic  chemists 
prepared  a  report  on  the  use  of  the  word  "protein,"  and  this  report  was 
adopted  by  a  joint  committee  of  the  American  Physiology  Society  and  the 
American  Society  of  Biological  Chemists. 

In  this  book,  therefore,  the  word  "  protein"  will  be  used  to  designate  the 
nitrogen-containing  foods,  which  consist  so  far  as  is  known  at  present  of  «- 
amino  acids  and  their  derivatives. 


148  Healthful  Living 

In  general  we  may  say  the  mineral  matter  of  food  is  not 
oxidized  to  produce  heat.  The  minerals  in  combination  with 
protein  are  known  as  organic  minerals.  There  are  inorganic 
minerals  in  the  body,  and  they  play,  an  important  part  in  the 
transfer  of  substances  from  the  blood  to  the  tissues  and  of 
waste  from  the  tissues  to  the  blood. 
Table  of  food  elements. 


Food  stuffs 


Nutritive 


Non-nutritive 


protein  nitrogenous 

fat  1 

carbohydrate  }  ^on-nitrogenous 

water 

mineral  matter 

waste 


The  carbohydrates  contain  a  greater  amount  of  carbon 
than  the  proteins;  remember,  however,  that  proteins  have 
some  carbon. 

Composition  of  foods.  —  Very  few  of  the  articles  of  food 
that  we  eat  consist  of  only  one  of  the  classes  of  food  ele- 
ments mentioned ;  most  foods  consist  of  several  elements 
combined.  Oatmeal,  for  instance,  contains  starch,  a  small 
proportion  of  fat,  a  large  proportion  of  protein,  some  mineral 
salts,  and  water.  Let  us  see  how  the  four  classes  are  repre- 
sented in  milk.  The  part  that  makes  it  liquid  is  water,  the 
sweetness  comes  from  the  sugar,  the  fat  rises  as  cream,  and 
the  curd,  from  which  cheese  is  made,  contains  casein,*  a  form 
of  protein. 

Sources  of  food  elements.  —  All  parts  of  plants  may 
furnish  food;  the  seed,  as  the  various  grains,  nuts,  and 
fruits ;  leaves,  as  lettuce,  cabbage,  dandelion ;  roots  and 
tubers,  as  potatoes,  beets,  turnips,  tapioca  (root  of  cassava) ; 
stem,  as  sago  (pith  of  sago  palm) ;  saps,  as  sugars  (of  cane, 
beets,  and  maple  tree). 

Protein.  —  Examples  of  proteins  are :  albumin,  in  white 
of  egg ;  gluten,*  the  sticky  or  gluey  part  of  grain  ;  casein,  in 
cheese  and  the  curd  of  milk ;  fibrin,  in  the  blood  of  animals ; 


Food  and  its  Elements  149 

myosin,*  the  basis  of  lean  meat ;  gelatin,  obtained  from  bones 
and  ligaments  by  boiling;  vegetable  protein,  in  beans  and 
peas ;  and  the  protein  of  nuts. 

Fats  and  oils.  —  Fats  and  oils  are  found  in  :  cream  of  milk, 
yolk  of  egg,  oil  of  nuts,  olives,  cottonseed,  cocoanut,  and 
fat  of  meat. 

Carbohydrates.  —  Carbohydrates  are  found  (a)  as  starch  in 
corn,  wheat,  rice,  oats,  and  other  grains,  potatoes,  cassava, 
arrowroot,  sago  (in  this  country  the  last  two  are  usually 
potato  starch  sold  under  those  names),  beans,  peas;  (6)  as 
sugar  in  sugar  cane,  sorghum,  dates,  honey  (almost  pure 
sugar),  bananas  (20  per  cent),  grapes,  fruits,  beets,  maple 
sap. 

Uses  of  food  in  the  body.  —  Food  has  two  uses  in  the 
body ;  first,  to  construct  and  repair  tissues ;  and  second,  to 
produce  energy  for  action.  This  action  may  be  muscular 
action,  which  can  be  seen,  or  it  may  be  nerve  impulses  or 
digestive  process,  the  results  of  which  only  are  seen.  The 
tissue  builders  are  protein  food  such  as  lean  meat,  eggs,  milk, 
wheat,  and  vegetable  proteins.  This  food  may  be  used  to 
produce  energy  if  the  fats  and  carbohydrates  are  insufficient 
in  amount.  The  fats  and  carbohydrates  furnish  to  a  large 
extent  the  energy  required.  To  some  extent  the  fat  of  food 
may  be  stored  in  the  body  as  fat,  but  only  when  taken  in 
amounts  above  that  required  for  producing  energy.  Fat 
in  the  body  in  large  amounts  is  not  desirable.  There  is  no 
advantage  and  there  is  a  distinct  disadvantage  in  storing 
up  a  great  excess  of  body  fat.  Such  a  condition  is  like  putting 
money  in  the  bank  without  receiving  any  interest  on  it.  The 
mineral  matter  is  absolutely  essential  in  the  formation  of 
bone  and  in  the  internal  transfer  of  substances.  The  usual 
mixed  diet  will  provide  .with  the  exception  of  sodium  chloride 
(common  table  salt)  sufficient  mineral  matter  for  the  body 
needs.  From  experiments  it  has  been  shown  that  alcohol 
is  oxidized  in  the  body,  furnishing  heat.  On  this  basis  it  is 


Healthful  Living 


sometimes  called  a  food.  Under  no  conditions,  however, 
does  it  serve  to  repair  old  or  build  new  tissue.  On  the  other 
hand,  it  is  such  a  powerful  drug,  with  such  habit-forming 
and  undesirable  properties,  that  it  is  not  to  be  considered 
as  a  desirable  food. 

Proportion  of  food  elements  in  a  normal  diet.  —  Ex- 
perience  has  shown  that  the  diet  best  suited  for  the  body 
should  contain,  besides  water,  protein  one  part,  fat  one  to 
two  parts,  and  carbohydrates  three  to  four  parts.  It  is  con- 
ceded that  people  eat  more  protein  than  is  necessary  or  de- 
sirable. Authorities  differ  in  their  recommendation,  but  it  is 
quite  generally  held  to-day  that  for  the  proper  nourishment 
of  the  body  the  problem  is  —  how  much  protein  shall  be  used. 
There  is  substantial  agreement  as  regards  the  energy  foods : 
the  fats,  and  the  carbohydrates.  The  following  dietaries* 
are  recommended  by  Atwater  and  Voit : 


ATWATER'S  STANDARDS 

PROTEIN 
GRAMS 

FAT 
GRAMS 

CARBO- 
HYDRATES 
GRAMS 

FUEL 
VALUE 
CALORIES 

Man  at  very  hard  muscular  work 
Man  at  hard  muscular  work     .     . 
Man  at  moderate  muscular  work 
Man  at  light  to  moderate  muscular 
work           

161 
138 
115 

103 

5500 
4150 
3400 

3050 

Man  at  sedentary  or  woman  at 
moderate  work 

92 

2700 

Woman  at  light  muscular  work     . 

83 

2450 

VOIT'S  STANDARDS 

PROTEIN 

FAT 

CARBO- 
HYDRATES 

FUEL 

VALUE 

GRAMS 

GRAMS 

GRAMS 

CALORIES 

Man 

at  hard  work 

133 

95 

437 

3270 

Man 

at  moderate  work   .... 

109 

53 

485 

2965 

It  will  be  noticed  that  in  Atwater's  table  the  amount  of 
energy  foods  is  omitted.     The  amount  of  fat  or  carbohy- 


Food  and  its  Elements  151 

drate  may  vary  as  long  as  the  total  amount  of  both  is  suf- 
ficient, together  with  the  protein,  to  supply  the  required 
energy.  From  the  table  of  food  values  on  page  153  select 
sufficient  amounts  of  fats  and  carbohydrates  to  yield,  to- 
gether with  the  protein,  the  calories  *  as  given  in  the  last 
column  in  Atwater's  Standards. 

Other  authorities  recommend  a  lower  protein  intake.  Dur- 
ing the  first  year  of  the  Great  War,  Thompson  and  Ballod 
investigated  the  food  consumption  of  Great  Britain.  Ac- 
cording to  Thompson,  a  British  physiologist,  the  protein 
intake  per  day  was  2.70  ounces  (1  ounce =31.1  grams) ;  esti- 
mate of  Ballod,  a  German  statistician,  was  3.75  ounces.  Both 
estimates  are  considerably  lower  than  the  protein  propor- 
tion given  by  Voit  or  Atwater.  Professor  Chittenden  of 
Yale  University  has  shown  that  health  may  be  maintained, 
for  a  long  period,  with  a  protein  intake  as  low  as  50  grams 
per  day.  The  experience  of  the  German  people  has  appar- 
ently proved  the  validity  of  the  lower  figure  for  protein.  It 
may  be  stated,  therefore,  that  the  protein  intake  daily  need 
not  exceed  100  grams. 

Calculation  of  food  values.  —  Food  is  of  use  in  the  body 
because  on  oxidizing  it  produces  heat.  The  heat  energy 
of  food  is  measured  in  terms  of  the  great  calorie,  and  a  great 
calorie  1  is  defined  as  that  amount  of  heat  necessary  to  raise 
one  kilogram  of  water  from  0°  to  1°  C,  or  one  pint  about 
4°  F.  By  experiment  it  has  been  found  that  the  following 
is  the  caloric  value  of  the  three  food  elements : 

1  gram  of  protein  yields  4.1  calories 

1  gram  of  fat  yields  9.3  calories 

1  gram  of  carbohydrate  yields  4.1  calories 

Now  the  number  of  calories  required  varies  with  the  size 
of  the  individual,  the  character  and  amount  of  work,  and  the 

1  This  is  the  Great  Calorie.  The  small  calorie  is  the  amount  of  heat  re- 
quired to  raise  one  gram  of  water  one  degree  C. 


152  Healthful  Living 

condition  of  health.     Langworthy  follows  Atwater's  Stand- 
ards and  gives  the  following  requirements  : 

Man  doing  no  muscular  work  .  .  .  2450  calories  a  day 
Man  doing  light  muscular  work  .  .  2700  calories  a  day 
Man  doing  light  to  moderate  muscular 

work 3050  calories  a  day 

Man  doing  moderate  muscular  work  3400  calories  a  day 
Man  doing  very  hard  muscular  work  5500  calories  a  day 

Lumbermen  working  during  the  winter  months  in  the 
Maine  woods  consume  food  in  a  single  day  that  yields  8000 
calories.  The  average  man  should  use  about  3000  calories  and 
this  will  be  obtained  by  taking  in  a  day  100  grams  of  protein, 
150  grams  of  fat,  and  350  grams  of  carbohydrate.  Brain 
workers  do  not  need  so  many  calories  as  laborers  in  the  field 
or  factory.  There  is  no  particular  kind  of  food  that  will 
serve  as  "  brain  food,"  although  fish  and  certain  prepared 
foods  are  often  claimed  to  have  that  virtue. 

The  caloric  needs  of  an  individual  form  the  basis  for  de- 
termining the  food  needs  of  a  nation.  It  is  with  scientific 
exactness,  therefore,  that  the  Belgian  Relief  Commission  cal- 
culated, "  until  after  the  harvest  of  1919  it  must  feed  ten 
million  people  in  Belgium  and  Northeastern  France.  They 
will  require,  in  twelve  months,  forty- two  million  bushels  of 
breadstuffs  and  over  three  hundred  million  pounds  of  meat  ; 
the  children  alone  must  have  seventy-three  million  pounds  of 
condensed  milk  and  cocoa  and  forty  million  pounds  of  sugar." 

The  study  of  the  following  table,1  arranged  from  Locke, 
will  show  the  quantity  and  the  caloric  value  of  different  foods. 
Select  from  this  table  and  write  on  the  blackboard  the  articles 
and  quantity  which  will  be  necessary  to  provide,  approxi- 
mately, 100  grams  of  protein,  150  grams  of  fat,  and  350  grams 
of  carbohydrate.  Compute  the  caloric  value.  In  some 
cases  it  will  be  desirable  to  select  two  portions  of  the  food. 

1  Selected  from  Food  Values  by  Edwin  A.  Locke 

h.  tbs.  =  heaping  tablespoonful 
h.  ts.  =  heaping  teaspoonful 


Food  and  its  Elements 


153 


M 

PROTEIN 

FAT 

CARBOHY- 

gg 

i 

a 

o 

DRATE 

0 

3  1 

QUAN- 

l! 

L 

&   --• 

0) 

"S 

8 

i 

"8  « 

H 

S   * 

ll 

FOOD 

TITY  OF 

fe   W 

5  « 

o  c 

1  '" 

O  <» 

2    ^ 

00    03 

S  * 

FOOD 

oO 

H  > 

«o 

§1 

>f 

c 

>St 

<«  2 

>% 

I-J  z 

WEIGH 
i] 

i~ 

K 

0 

O 

r 

j£ 

0     C 

'E  ,0 

S 
o 

I 

Roast  beef  .     . 

1  slice 

100 

48.20 

22.30 

91.4 

28.6 

266 

357 

357 

Roast  lamb 

1  slice 

175 

50.33 

14.78 

60.6 

9.53 

88.6 





200 

150 

Mutton  chop  . 

1  chop 

100 

71.80 

22.60 

92.7 

4.5 

41.9 





135 

135 

Fried  ham  .     . 

1  slice 

35 

12.81 

7.77 

31.9 

11.62 

108.1 





400 

140 

Butter    .     .     . 

1  ball 

15 

1.65 

0.15 

0.6 

12.75 

118.6 





795 

119 

Cheese  (Amer.) 

1  cu.  in. 

20 

6.32 

5.70 

23.6 

7.18 

66.7 

0.6 

.2 

453 

91 

Milk  (whole)    . 

1  glass 

220 

191.40 

7.26 

29.8 

8.80 

21.8 

11 

45.1 

72 

157 

Egg  (boiled)     . 

1  egg 

50 

36.60 

6.60 

27.1 

6 

55.8 





169 

83 

Baked  beans    . 

3  h.  tbs. 

150 

91.17 

10.83 

44.4 

12.76 

118.7 

32.84 

134.6 

199 

298 

Carrots  .     .     . 

3  h.  tbs. 

100 

93.40 

.53 

2.2 

.17 

1.6 

3.39 

13.9 

18 

18 

Corn  (green)    . 

1  ear 

100 

72.6 

3.07 

12.6 

1.10 

10.2 

18.78 

77 

100 

100 

Peas  (green)     . 

3  h.  tbs, 

92 

67.90 

6.16 

25.3 

3.13 

29.11 

3.43 

55.1 

119 

110 

Potato  (baked) 

1  med. 

130 

90.87 

3.77 

15.5 

.20 

1.9 

32.07 

131.5 

114 

149 

Apple      .     .     . 

av.  size 

150 

94.90 

.45 

1.8 

.45 

4.2 

16.2 

66.4 

49 

72 

Orange    .     .     . 

av.  size 

250 

158.5 

1.5 

6.2 

.25 

2.3 

21.25 

87.1 

37 

96 

Marmalade 

1  h.  tbs. 

30 

4.35 

.18 

.7 

.03 

.3 

25.35 

103.9 

349 

105 

Bread  (white) 

1  slice 

30 

10.59 

2.76 

11.3 

.39 

3.6 

15.93 

65.3 

268 

80 

Bread  (whole 

wheat)      .     . 

1  slice 

42 

16.13 

4.07 

16.7 

.38 

3.5 

20.87 

85.6 

251 

106 

Crackers 

(graham) 

1  cracker 

8 

.43 

.80 

3.3 

.75 

7.0 

5.90 

24.2 

429 

34 

Ham  sandwich 

1  sand. 

70 

24.15 

7.28 

29.8 

10.07 

93.7 

26.65 

109.3 

332 

233 

Oatmeal       .     . 

2  h.  tbs. 

100 

84.50 

2.80 

11.5 

.50 

4.7 

11.50 

47.2 

63 

63 

Rice  (boiled)    . 

1  h.  tbs. 

100 

72.50 

2.80 

11.5 

.10 

.9 

24.40 

100 

112 

112 

Shredded 

wheat  bis.     . 

1  biscuit 

29 

2.35 

3.05 

12.5 

.41 

3.8 

22.59 

92.6 

375 

109 

Spaghetti     .     . 

3  h.  tbs. 

145 

111.21 

4.52 

18.5 

2.81 

26.1 

25.76 

105.6 

103 

150 

Cake  choc.  .     . 

av.  slice 

70 

14.30 

4.34 

17.8 

5.67 

52.7 

44.87 

184 

364 

255 

Sugar  cookies  . 

1  cooky 

11 

.91 

.77 

3.2 

1.12 

10.4 

8.05 

33 

423 

47 

Granulated 

sugar  .     .     . 

1  h.  ts. 

10 

~ 

10 

41 

410 

41 

The  diet  of  different  peoples.  —  Milk  has  an  excess  of 
nitrogen,  and  oatmeal  an  excess  of  carbon ;  oatmeal  and 
milk  form  a  perfect  food,  and  it  is  not  surprising  that  the 
Scotch  people,  with  whom  it  has  been  a  chief  food,  are  a 
sturdy  race.  Potatoes  are  mostly  starch  and  water;  the 
starch  in  them  is  nearly  nine  times  as  much  as  the  protein, 
and  an  Irishman  who  tried  to  live  on  potatoes  alone  would 
have  to  eat  seven  pounds  a  day  to  get  enough  protein.  By 


154  Healthful  Living 

eating  milk  and  eggs  also,  he  can  get  along  on  half  the 
amount  of  potatoes  named  above.  Every  Irish  peasant  is 
said  to  keep  a  cow  and  chickens.  The  Mexicans  eat  bread 
made  of  corn  meal,  and  supply  the  protein  by  using  beans 
as  a  constant  article  of  diet.  The  Zulus  live  on  cracked 
corn  by  adding  milk  to  it.  The  Arabs  live  on  barley  and 
camels'  milk,  rarely  eating  the  camels'  flesh.  Hundreds  of 
millions  of  people  in  Asia  (the  Hindoos,  Chinese,  and  others) 
subsist  mainly  on  rice,  which  is  more  nearly  pure  starch 
than  any  of  the  grains,  containing  only  6  per  cent  of  protein, 
about  half  as  much  as  wheat  and  corn;  the  chief  addition 
they  make  is  butter  or  other  fat,  and  beans,  which  contain 
vegetable  protein.  Their  meager  diet  may  partly  account 
for  their  lack  of  energy  and  bravery,  and  the  ease  with  which 
they  are  conquered  and  controlled  by  European  nations. 
The  greatness  of  a  people  is  greatly  influenced  by  their  diet. 

The  body's  method  of  regulating  the  food  supply.  —  We 
should  not  think  that  the  food  eaten  must  be  regulated  with 
the  greatest  precision.  Any  reasonable  excess  will  pass 
through  the  canal  unabsorbed,  without  great  injury  to  the 
body.  The  lack  of  any  of  the  necessary  elements  will  be 
well  tolerated  for  a  time  until  a  craving  for  a  certain  kind 
of  food  will  lead  later  to  the  supply  of  the  elements  needed. 
If  a  person  feels  bad,  or  the  digestion  seems  weak,  some  will 
advise  dieting.  There  is  a  tendency  among  certain  writers 
on  hygiene  to  overrate  the  importance  of  this  subject.  If 
the  laws  of  health  in  regard  to  fresh  air,  muscular  exercise, 
sleep,  cleanliness,  temperature,  and  abstinence  from  the  use 
of  stimulants  be  observed,  our  appetites  usually  will  be  a 
sufficient  guide  in  the  matter  of  diet.  These  matters  should 
first  be  looked  to,  and  dieting  then  will  probably  become 
unnecessary. 

It  is  an  instructive  and  important  fact,  that  too  much 
consciousness  of  what  is  eaten  and  too  much  dwelling  on 
what  might  be  the  consequence  of  eating  this  food  or  that 


Food  and  its  Elements  155 

food,  may  interfere  seriously  with  good  digestion.  If  the 
sense  of  taste  is  not  abused,  but  its  promptings  treated  with 
great  respect,  we  shall  preserve  a  useful  guide  which  will 
tell  us  more  perfectly  what  is  needed  than  any  scientific 
table  can  do.  Food  that  brings  discomfort  after  eating, 
however,  should  not  be  eaten. 

The  work  of  enzymes  *  in  digestion.  —  The  preparation  of 
food  in  the  body  so  that  it  can  be  assimilated  (taken  up  by 
the  cells)  is  a  process  in  which  certain  digestive  juices  act 
upon  the  food  mass.  The  action  of  these  juices  is  effective 
because  they  contain  substances  which  break  up  the  food 
masses  into  smaller  units.  This  breaking  up  is  accomplished 
by  bodies  known  as  enzymes.  It  is  important  to  under- 
stand what  their  nature  is. 

Example  of  enzyme  action.  —  The  souring  of  milk,  the 
putrefaction*  of  animal  substances,  and  the  fermentation  of 
food  materials  have  been  explained  in  various  ways  in  past 
years.  These  phenomena  led  to  investigations,  and  it  was 
learned  that  the  chemical  action  going  on  differed  from  other 
chemical  action  in  that  the  substance  producing  the  change 
was  not  destroyed  or  used  up  in  the  reaction.  Pasteur 
showed  that  fermentations  were  due  to  bacterial  action.  It 
was  later  learned  that  there  were  other  substances  produced 
by  living  cells  which  would  cause  changes  in  food.  These 
substances  are  known  as  enzymes.  They  have  special 
names,  for  example,  the  enzyme  of  the  saliva  is  ptyalin,  of 
the  gastric  juice,  pepsin  and  rennin,  of  the  pancreatic  juice, 
trypsinogen,  lipase,  etc.  Enzymes  act  to  produce  a  chemical 
change,  but  they  themselves  do  not  enter  into  the  reaction. 
What  is  catalysis*  in  chemistry?  Are  enzymes  similar  to 
catalyzers  ? 

The  action  of  the  enzyme  is  always  specific.  The  ptyalin 
of  the  saliva  changes  starch  to  sugar,  but  it  has  no  effect  on 
protein.  Each  enzyme  acts  on  a  particular  kind  of  food 
material ;  it  is  fitted  to  it  "  as  a  key  to  its  lock." 


156  Healthful  Living 

Classification  of  enzymes.  —  If  digestion  is  thought  of  as  a 
process  similar  to  the  work  of  a  stone  cutter,  who  takes  a 
rough  mass  of  stone  and  cuts  it  up  into  blocks  of  a  certain 
size  to  fit  into  a  particular  place  in  the  building,  then  the 
action  of  enzymes  may  be  likened  to  the  chisels  which  break 
the  stone.  This  breaking  down  of  food  compounds  into 
smaller  units  is  called  "  splitting,"  and  so  we  speak  of  protein- 
splitting  enzymes,  fat-splitting  enzymes,  etc. 

1.  Protein-splitting  enzymes.  —  Pepsin  (gastric  juice)  and 
trypsinogen   (pancreatic  juice).     They  cause  in  a  reaction 
with  water  a  splitting  of  the  protein  into  smaller  units 
capable  of  absorption  by  the  body  cells.     This  action  with 
water  is  called  hydrolysis.* 

2.  Starch-splitting  enzymes. — Ptyalin  (saliva)  and  amylase 
(pancreatic  juice) .    The  action  in  this  case  is  one  of  hydrolysis. 
The  starch  molecule  is  converted  into  a  less  complex  one,  a 
sugar,  in  the  form  of  two  molecules  of  sugar  (disacchride) . 

3.  Sugar-splitting    enzymes.  —  These    split     the     disac- 
chrides  into   monosacchrides.      Examples,   maltase,   which 
con  verts,  maltose  into  two  molecules  of  dextrose;  invertase, 
which  splits,  cane   sugar   into    dextrose  and  levulose ;   and 
lactase,  which  splits  milk  sugar  into  dextrose  and  galactose. 
The  following  f ornlula  *  indicates  what  this  change  is  : 

Ci2H22Oii+H20+maltase  =  C6Hi206+C6Hl2O6+ maltase 

III  III 

maltose         water        enzyme        dextrose         dextrose       enzyme 

The  enzyme  maltase  causes  the  change;  it  is  not  de- 
stroyed or  used  up  in  the  process. 

4.  Fat-splitting  enzymes.  —  Lipase  (pancreatic  juice  and 
bile).     This  acts  by  hydrolysis;  as, 

C3H5(Ci8H3502)3+3H20+lipase  =  C3H5(OH)3+3(C18H3602)  4-lipase 

I  I  I  I  I 

Tristearin  water    enzyme         glycerin        stearic  acid    enzyme 

The  fat  mass  tristearin  found  in  beef  fat  is  broken  down 
into  glycerin  and  stearic  acid. 


Food  and  Us  Elements  157 

GLOSSARY 

Albuminoid.  —  Substance  similar  in  composition  to  albumin. 

Calorie.  —  Food  when  it  undergoes  combustion  produces  heat. 
This  heat  is  measured  by  standards  and  th'e  unit  of  heat  used 
as  the  standard  is  the  calorie.  -  The  greater  calorie  is  the 
amount  of  heat  required  to  raise  one  kilogram  of  water  one 
degree  C.  When  speaking  of  the  caloric  value  of  food,  it  is 
the  greater  calorie  that  is  meant. 

Casein.  —  The  name  of  the  protein  of  milk  after  it  has  been  coagu- 
lated by  the  enzyme  rennin.  Before  coagulation,  the  protein 
is  called  caseinogen. 

Catalysis.  —  A  chemical  change  brought  about  in  a  chemical  com- 
pound by  an  agent  that  does  not  enter  into  the  action  of  the 
change  in  a  chemical  way. 

Dietary.  —  A  systematic  arrangement  of  the  diet. 

Enzyme.  —  A  substance  that  induces  digestive  chemical  action 
in  the  food  elements  but  does  not  enter  itself  into  the  chemical 
change.  The  ptyalin  of  the  saliva  is  an  enzyme. 

Formula.  —  A  group  of  symbols  showing  the  composition  or 
structure  of  a  chemical  compound. 

Gelatinoid.  —  A  substance  similar  in  composition  to  gelatin. 

Globulin.  —  One  of  the  proteins.  The  chief  globulins  in  the 
body  are  serum  globulin  and  fibrinogen  of  the  blood,  myo- 
sinogen  of  muscle,  and  globin  in  combination  with  hematin 
in  the  red  corpuscle. 

Gluten.  —  An  essential  element  in  the  cereal  wheat.  It  gives  to 
the  flour  important  nourishing  characteristics.  It  is  a  pro- 
tein. 

Haemoglobin.  —  The  iron-containing  substance  in  the  red  corpuscle. 
Chiefly  noted  for  its  ability  to  carry  oxygen  in  chemical  com- 
bination. It  is  formed  from  a  globulin,  globin,  and  an  iron 
radical  called  hematin. 

Hydrolysis.  —  The  chemical  decomposition  of  a  compound  that 
ensues  when  water  (H2O)  is  absorbed  by  it. 

Myosin.  —  Formed  from  myosinogen.  It  comprises  75  per  cent 
of  the  protoplasm  of  muscle  tissue.  It  is  a  protein.  At 
death  it  coagulates,  and  causes  rigor  mortis. 

Nutritive.  —  Having  properties  which  promote  nutrition. 

Putrefaction.  —  The  act  of  breaking  down  of  an  organic  compound 
It  represents  decay  and  decomposition. 


CHAPTER   X 
THE    DIGESTION    OF    FOOD 

I.   The  Structure  and  Functions  of  the  Alimentary  Canal. 
The  mouth 
The  pharynx 
The  esophagus 
The  stomach 
The  small  intestine 
The  large  intestine 
II.    The  Liver. 

Anatomy 
Functions 

III.  Diagram  of  Digestive  Mechanism. 

IV.  The  Waste  Products  from  Food  Elements. 


The  structure  and  functions  of  the  alimentary  canal.  — 
Food,  in  order  to  be  of  service  to  the  body,  must  undergo 
several  changes.  Its  nutritive  portion  must  be  separated 
from  the  non-nutritive;  and  the  former  must  be  made 
soluble,  or  in  fit  condition  to  be  taken  up  by  the  blood  and 
carried  to  the  tissues.  This  process  is  called  digestion,  and 
the  assemblage  of  organs  by  which  it  is  carried  on  is  called 
the  digestive  system.  The  tube  which  forms  the  receptacle 
for  the  food  during  digestion  is  called  the  alimentary  *  canal. 
In  the  carnivora,  or  flesh-eating  animals,  whose  food  con- 
tains but  a  small  amount  of  indigestible  matter,  the  ali- 
mentary canal  is  comparatively  short,  being,  when  stretched 
out,  only  three  or  four  times  the  length  of  the  body.  In  the 
herbivora,  or  grass-eating  animals,  the  canal  is  thirty  times 
the  length  of  the  body.  In  the  hog,  which  is  omnivorous 

158 


The  Digestion  of  Food  159 

("  all-eating  "),  it  is  ten  times  the  length  of  the  body.  If 
man's  trunk  only  is  counted,  the  canal  is  twelve  times  as 
long ;  if  his  height  is  counted,  the  canal  is  six  times  as  long. 

The'alimentary  canal  has  three  coats  in  its  walls  throughout 
its  whole  length.  What  is  each  for?  The  inner  coat,  or 
lining,  is  a  delicate  epithelial  tissue  called  the  mucous  mem- 
brane. It  forms  a  smooth  lining  to  prevent  friction,  and 
secretes  a  mucus  which  serves  the  same  purpose.  The  next 
coat  is  the  submucous  coat ;  it  is  of  elastic  connective  tissue, 
and  serves  to  toughen  and  strengthen  the  wall,  and  to  bind 
the  mucous  coat  to  the  muscular  coat.  Outside  of  this  is 
the  third  coat.  It  is  composed  of  several  layers  of  invol- 
untary muscular  tissue,  which,  by  its  contraction,  causes  the 
food  to  move  along  the  canal  (Fig.  114). 

In  the  walls  of  the  alimentary  canal  are  numerous  blood 
vessels  and  lymphatics.  Opening  on  its  inner  surface  are 
mouths  of  ducts  from  the  various  glands  of  the  digestive 
system.  Some  of  the  glands  are  of  considerable  size  and  lie 
outside  of  the  canal ;  others  are  very  minute  and  are  em- 
bedded in  the  walls  of  the  canal ;  their  secretions  render  the 
food  soluble. 

When  we  swallow  food  or  drink,  we  are  accustomed  to  say 
that  it  is  in  the  body,  but  anatomically  and  physiologically 
this  is  not  correct.  It  is  on  the  outside  anatomically,  be- 
cause the  mucous  membrane  is  continuous  with  the  skin, 
which  is  the  external  covering  (Fig.  106).  It  is  on  the  out- 
side physiologically,  because  the  food  must  pass  through  the 
mucous  membrane  before  it  can  be  assimilated  by  the  tissues 
and  become  of  use  to  the  body. 

A  lean  person  often  eats  a  great  deal,  expecting  to  get  fat, 
and  finds  that,  although  he  has  swallowed  the  food,  the 
nourishment  has  never  really  entered  his  body. 

The  mouth.  —  The  food  is  held  in  the  mouth  for  a  short 
time  while  it  is  mixed  with  the  watery  alkaline  fluid  called 
the  saliva,  and  is  ground  up  fine  by  the  teeth.  The  partition 


i6o 


Healthful  Living 


between  the  nose  and  the  mouth  is  formed  by  the  palate 
bones,  covered  with  mucous  membrane.  The  larger  part 
of  the  roof  of  the  mouth  is  formed  by  these  bones  and  is 
called  the  hard  palate.  The  roof  is  completed  in  the  rear 
by  the  fleshy  soft  palate.  The  floor  of  the  mouth  is  occupied 


FIG.  106.  —  The  food  materials  must  pass  the  mucous  membrane  lining 
of  the  alimentary  tract  before  they  are  within  the  body.  The  liver  is  dis- 
placed upward  to  show  the  parts  under  it. 

mostly  by  the  tongue ;  the  lips  form  the  front  wall,  and  the 
cheeks  the  side  walls.  The  cheek  is  composed  partly  of  a 
large  flat  muscle  called  the  buccinator  (trumpeter,  because 
used  in  blowing  a  trumpet) .  The  contraction  of  the  trump- 
eter muscles,  together  with  the  movements  of  that  flat 
muscle  called  the  tongue,  keeps  the  food  between  the  teeth 
in  the  act  of  chewing,  or  mastication. 

Salivary  Glands.  —  There  are  three  pairs  of  glands  that 


The  Digestion  of  Food  161 

secrete  saliva.  In  structure  one  of  these  glands  with  its 
duct  resembles  a  minute  bunch  of  grapes  with  a  hollow  stem. 
The  largest,  called  the  parotid,  is  just  beneath  the  skin  in 
front  of  the  ear.  Its  duct  opens  into  the  mouth  in  the  upper 
jaw  opposite  the  second  molar  tooth.  This  gland  swells  in 
a  disease  called  the  mumps.  The  next  largest  gland  is  the 
submaxillary,  lying  within  the  angle  of  the  lower  jaw.  Its 
duct  opens  into  the  floor  of  the  mouth.  The  smallest,  the 
sublingual,  lies  farther  to  the  front ;  both  glands  of  the  pair 
lie  beneath  the  tongue,  and  open  by  a  number  of  ducts.  The 
fluid  produced  by  these  glands  becomes  mixed  with  the  mucus 
from  the  mucous  membrane  of  the  mouth  and  is  called  the 
saliva. 

Saliva.  —  Saliva  is  a  thin,  colorless,  alkaline  liquid,  slightly 
sticky,  and  often  containing  air  bubbles.  The  digestive  en- 
zyme of  the  saliva  -is  ptyalin,  which  has  the  power  to 


FIG.  107.  —  Cells  of  the  salivary  gland.  A,  after  rest;  B,  after  a  short 
period  of  activity  ;  C,  after  a  prolonged  period  of  activity.  Shriveling  and 
loss  of  granules  occur. 

change  starch  to  malt  sugar.  Maltase  is  also  present 
which  changes  the  malt  sugar  to  dextrose.  From  one  to 
three  pints  of  saliva  are  produced  daily  (Fig.  107).  Its  flow  is 
excited  by  the  act  of  chewing  and  by  anything  held  in  the 
mouth,  especially  if  it  be  of  an  agreeable  taste  or  odor. 
Hunger,  or  the  sight  or  thought  of  agreeable  food,  makes 
the  "  mouth  water  "  by  stimulating  the  cells  in  the  glands 
to  activity  by  means  of  the  nerves.  But  by  far  the  most 
powerful  of  all  the  excitants  to  the  salivary  flow  is  dryness 


162 


Healthful  Living 


Right  Tons/7 
Poster/or 
of  Pharynx 


Soft  Palate 


Uvula 


•Left  Tons/7 


of  the  food.  Only  one  fourth  as  much  saliva  is  deposited 
in  the  same  length  of  time  when  eating  oatmeal  and  milk 
as  when  eating  crackers  or  dry  toast. 

The  Tonsils.  —  The  tonsils  *  (Fig.  108)   are  large  lymph 
glands.     They  are  oval  in  shape  but  vary  greatly  in  size  in 

different  people. 
They  become  in- 
fected frequently 
and  cause  in  this 
way  many  cases  of 
heart  disease  and 
rheumatism.  * 
Many  people  who 
suffer  from  rheu- 
matism could  be 
cured  by  proper 
treatment  of  in- 
fection existing 
in  the  tonsils  or 
teeth.  The  ton- 
sils can  be  re- 
moved entirely 
without  injury  to 
the  health,  and  if 
they  are  diseased,  removal  of  them  will  improve  the  health. 
The  use  of  tobacco  is  a  common  cause  of  diseases  of  the 
throat.  It  causes  a  dry  ness  and  thirst,  and  frequently  leads 
those  who  use  it  to  take  alcoholic  drinks.  Often  the  habit 
of  smoking  produces  a  troublesome  disease  called  smokers' 
sore  throat,  which  can  be  cured  only  after  smoking  has  been 
discontinued.  The  heat  of  smoking  is  very  trying  to  the 
organs,  although  not  so  injurious  to  them  as  the  poison  of 
the  tobacco. 

Absorption  *  from  the  Mouth.  —  The  passage  of  digested 
food  into  the  blood  vessels  is  an  important  sequel  of  the 


FIG.  108.  —  Structures  within  the  mouth  as  seen 
when  it  is  open  and  tongue  depressed.  (Modified 
after  Coakley.) 


The  Digestion  of  Food 


163 


digestive  process.     A  little  of  the  water  containing  sugar 

and  salts  is  absorbed  from  the  mouth  directly  into  the  blood 

vessels.     Poisonous  substances  may  sometimes  be  absorbed 

from  the  mouth  in  sufficient  quantities  to  produce  death. 

If  a  drop  or  two  of  prussic 

acid  should  be  placed  on 

the    tongue    or    on    the 

mucous  membrane  of  the 

mouth,  death  would  occur 

in  a  few  minutes,  although 

not  a  particle  of  it  had 

reached      the      stomach. 

Boys  who  take  their  first 

chew  of  tobacco  learn  in  a 

disagreeable  way  that  the 

entire   body  may   be   af- 

fected by  absorption  from 

the  mouth.     The  absorp- 

tion of  food  in  the  mouth 

is  insignificant  in  amount 

compared  to  the  absorp- 

tion that  takes  place  in 

the  small  intestine. 

The  pharynx  *  (f  ar'inks)  . 

-A  muscular  bag  open- 

ing     from     the     nose     and 

month      frmr    anrl     a     half 
niOUtn,     lOUr    and     a    halt 

inches       in       length,       lies 

atraiW  thp  sninnl  polumn 
nurnn. 

It  is  commonly  called  the 
throat.  There  is  an  air  passage  from  nose  to  lungs  and  a  food 
passage  from  mouth  to  stomach.  They  cross  each  other,  and 
the  intersection  is  called  the  pharynx.  There  are  seven 
openings  from  the  pharynx  :  one  to  the  mouth,  one  below 
the  mouth  into  the  trachea,  one  behind  the  trachea  into  the 


FIG.  109.  —  Mouth  and  upper  part  of 


d,  larynx;  e,  epiglottis;  /,  soft  palate 
and  uvula  ;  0,  opening  of  left  Eustachian 
tube  ;  ^  opening  of  left  lachrymal  duct  ; 
i,  hyoid  bone  ;  k,  tongue  ;  I,  hard  palate  ; 

m'  w'  base  of  skull;  °»  p'  9'  the  scroll~ 
like  or  turbinated  bones  .  Tt  tonsiL 


164 


Healthful  Living 


(Esophagus, 


esophagus,  and  two  pairs  of  openings  in  the  upper  pharynx  ; 
one  of  these  pairs  is  to  the  nasal  passages,  and  the  other 
pair  is  into  the  Eustachian  tubes,  which  lead  to  the  ears. 
When  swallowing,  all  of  the  openings  close  but  the  one  to 
the  mouth  and  the  one  to  the  esophagus.  (See  Plate  VII.) 

The  upper  part  of  the  pharynx,  and  thus  the  openings  to 
the  nose  and  ears,  can  be  closed  by  raising  the  tip  of  the  soft 
palate,  or  uvula,*  against  the  back  wall  of  the  pharynx 

(Fig.  109).  Sudden 
laughter  or  coughing 
while  swallowing  may 
cause  the  soft  palate 
to  relax,  and  then  a 
portion  of  the  food 
or  drink  is  sometimes 
forced  into  the  nose. 
The  opening  to  the 
trachea  can  be  closed 
in  two  ways  :  by  the 
vocal  cords  contract- 
ing and  approaching 
one  another;  or  by 

FIG.   110.  —  The   stomach,    duodenum,    and    the  drawing   Upward 


Stomach 
'Pancreatic  Duct 


gall  bladder  laid  open. 

pleted  the  bile  from  the  liver  backs  up  into  the 

gallbladder. 


When  digestion  is  com-       f    ,,       larVnY  tn 
(       tne   iarynx  * 


epiglottis.*     The 
opening     from     the 

mouth,  called  the  fauces,  can  be  closed  by  the  contraction 
of  upright  muscles,  called  the  pillars  of  the  fauces,  which 
connect  the  posterior  part  of  the  soft  palate  and  the  base 
of  the  tongue.  These  muscles  come  together  in  the  middle 
like  sliding  doors.  There  are  two  of  them  on  each  side, 
and  the  tonsils  lie  between  them  (Fig.  108).  The  tip  of 
the  soft  palate  hangs  down  between  the  pillars,  and  is 
called  the  uvula.  By  looking  into  a  mirror  with  the 
mouth  very  wide  open  and  the  tongue  flattened,  you  can 


The  Digestion  of  Food  165 

see  the  palates,  the  pillars,  the  uvula,  and  perhaps  the 
tonsils. 

The  esophagus.  —  The  esophagus,  which  conducts  the 
food  to  the  stomach  (Figs.  109,  110),  opens  from  the  lower 
part  of  the  pharynx.  It  is  about  nine  inches  long,  and  lies 
in  front  of  the  spinal  column  and  behind  the  trachea.  It 
has  the  three  layers  found  elsewhere  in  the  alimentary  canal, 
and  its  walls  are  soft  and  he  collapsed  when  no  food  or  drink 
is  passing.  The  food  is  under  reflex  control  after  passing 
the  fauces.  The  contraction  of  the  pharynx  presses  the  food 
down  into  the  esophagus.  A  ring  of  the  muscular  tube  con- 
tracts just  above  the  morsel.  This  contraction  runs  down 
to  the  stomach,  forcing  the  food  before  it  as  if  a  tight  ring 
were  slipped  down  over  the  esophagus.  A  contraction  of 
any  part  of  the  alimentary  canal  in  this  manner,  as  if  a  wave 
were  traveling  along,  is  called  a  peristalsis.*  While  a  horse 
is  drinking,  the  peristaltic  waves  of  the  esophagus  may  be 
plainly  seen  along  the  neck  (Plate  V) . 

The  stomach.  —  The  esophagus  pierces  the  diaphragm  to 
the  left  of  the  center  and  enlarges  into  a  pouch  called  the 
stomach.  This  organ  lies  just  under  the  diaphragm,  mostly 
on  the  left  side  of  the  abdomen  and  half  covered  by  the  lower 
ribs.  It  is  capable  of  holding  about  two  quarts.  When 
full,  it  is  about  a  foot  long  and  five  inches  broad.  Its  shape 
is  not  easily  described  (Fig.  110).  It  is  placed  across  the 
abdomen,  and  its  left  end  is  the  larger.  Its  outline  is 
curved  inward  above  and  outward  below.  When  empty, 
it  flattens  and  its  walls  touch,  and  the  mucous  lining 
then  lies  in  deep  wrinkles  or  folds.  The  opening  where 
the  esophagus  ends,  and  through  which  the  food  enters, 
is  called  the  cardia,  because  it  is  near  the  heart.  The 
opening  where  the  intestines  begin,  and  through  which 
the  food  leaves,  is  called  the  pylorus*  (gate  keeper);  both 
openings  can  be  closed  by  circular  muscles  in  their 
walls. 


i66 


Healthful  Living 


Movements.  —  Anything  taken  into  the  stomach  causes 
peristalsis.  The  food  is  caused  to  go  from  the  esophagus 
to  the  left  of  the  cardiac  orifice,  then  down  to  the  right  and 
back  again,  the  circuit  from  left  to  right,  then  from  right 
to  left,  taking  from  one  to  three  minutes  according  to  the  ac- 
tivity of  the  peristalsis.  The  muscular  fibers  in  the  walls 

, of    the  stomach    are    in 

three  layers  (Fig.  Ill) ; 
one  layer  runs  length- 
wise, another  around, 
b  and  the  third  obliquely, 
so  that  the  varied  con- 
tractions cause  the  food 
to  become  thoroughly 
mixed  with  the  digestive 
juice. 

Secretion.  —  The  secre- 
tion of  the  stomach  is 
called  gastric  juice.  This 

FIG.  111.  — A  section  through  the  wall  is   a  yellowish    fluid    and 
of  the  stomach.     (Magnified  15  diameters.)  .  »  , 

a,  surface  of  the  mucous  membrane,  show-  Consists  Ot   Water  having 

ing   the   openings   of    the   gastric    glands;  in  solution  hydrochloric* 
6,    mucous    membrane,    composed    almost         .  ,  ,     , 

entirely  of  glands  ;  c,  submucous,  or  areolar  acid    and    *WO    enzymes, 

tissue;     d,    transverse    muscular     fibers;  These     remarkable    Sub- 
e,   longitudinal   muscular   fibers ;    /,    peri-  , . , 

tonealcoat.  stances,   although  exist- 

ing in  very  small  quanti- 
ties, are  able  to  change  the  composition  of  large  quantities 
of  food.  In  times  of  rest,  when  there  is  no  food  present,  the 
mucous  membrane  of  the  stomach  is  of  a  pale  red  color.  But 
when  food  is  introduced,  a  change  at  once  takes  place.  The 
membrane  becomes  charged  with  blood  and  consequently 
turns  to  a  deep  red  color.  The  gastric  juice,  secreted  by 
many  small  glands  (Fig.  112),  appears  on  the  walls  of  the 
stomach,  and  peristaltic  action  begins. 

One  enzyme  of  the  gastric  juice,  called  rennin,  acts  by 


The  Digestion  of  Food 


coagulating  milk,  a  change  somewhat  like  the  coagulation 
of  the  blood.  It  causes  coagulation  by  acting  upon  the 
protein  part  of  the  milk.  It  is  especially  abundant  in  child- 
hood. The  other  enzyme,  called  pepsin,  softens  the  protein 
part  of  food  and  reduces  it  to  .peptone,  in  which  form  it  is 
soluble  in  water.  Pepsin,  however,  can  act  only  when  the 
hydrochloric  acid  has  ac- 
cumulated to  an  amount 
sufficient  to  neutralize*  the 
alkaline  condition  caused  by 
the  saliva.  This  usually  re- 
quires about  thirty  or  forty 
minutes.  The  hydrochloric 
acid,  by  its  presence  in 
sufficient  quantity,  not  only 
enables  the  pepsin  to  act, 
but  also  prevents  fermenta- 
tion of  the  food  and  kills  all 
germs  that  may  enter  the 
stomach. 

The  saliva  continues  its 
work  even  in  the  stomach 
until  neutralized  by  the  acid. 
The  pepsin  then  begins  to 
act.  The  outside  of  the  food 
particles  is  acted  upon  first, 
and  this  digested  part  is  then 
rubbed  off  by  the  peristaltic 
movements,  and  the  next  layer  is  acted  upon.  Its  action  is 
confined  to  the  protein.  In  fat  meat  the  albuminous  walls 
of  the  cells  are  eaten  away  and  the  fat  is  set  free  but  not 
digested.  Starch  may  also  be  set  free  from  albuminous 
envelopes.  The  food  is  thus  reduced  to  a  semifluid  condi- 
tion and  is  called  chyme.* 

After  the  food  has  been  reduced  to  chyme,  the  pylorus 


FIG.  112. —  Three  glands  of  the 
stomach,  e,  epithelium  at  inner  sur- 
face of  stomach  ;  m,  mouth  of  gland  ; 
p,  principal  cells  of  gland ;  ov,  ovoid 
cells ;  c,  connective  tissue  below  and 
between  the  glands. 


1 68  Healthful  Living 

opens  every  minute  or  two,  permitting  a  little  of  the  chyme 
to  escape  into  the  intestine.  But  if  some  hard  object,  as  a 
button,  or  a  lump  of  raw  starch  from  an  unripe  apple  in- 
sufficiently masticated,  enters  the  stomach,  the  pylorus, 
after  a  while,  will  become  fatigued  and  will  relax  and  allow 
it  to  pass  without  becoming  semifluid. 

Action  of  the  Acid  Chyme.  —  As  the  acid  chyme  passes 
into  the  duodenum  it  causes  an  important  chemical  action. 
When  the  acid  chyme  comes  in  contact  with  the  mucous 
membrane  of  the  intestinal  wall  some  of  it  is  absorbed,  and 
this,  acting  on  an  enzyme  (prosecretin)  in  the  intestinal  cells, 
causes  the  formation  of  another  enzyme,  secretin.  The 
secretin  passes  into  the  blood  and,  coming  to  the  liver, 
pancreas,  and  cells  of  the  intestinal  walls,  causes  these  organs 
to  pour  out  their  digestive  juices.  For  many  years  it  was  not 
understood  how  the  pancreas  or  liver  could  know  when  to 
free  their  digestive  juices,  because  the  food  did  not  come  in 
direct  contact  with  their  cells.  It  is  the  secretin,  therefore, 
which  tells  these  organs  when  they  must  give  up  their  juices 
for  digestive  purposes.  The  secretin  causes  the  flow  of  the 
pancreatic  juice,  the  bile,  and  the  intestinal  juice  (page  184). 

Absorption  from  the  Stomach.  —  A  slight  absorption  may 
take  place  in  the  stomach  of  a  portion  of  the  protein  digested 
there.  Some  of  the  sugar  resulting  from  the  salivary  diges- 
tion of  starch  by  the  saliva  may  also  be  absorbed.  Nearly 
all  the  absorption  of  the  food  takes  place  in  the  small  in- 
testine, and  it  is  there  likewise  that  most  of  the  digestion 
occurs ;  for,  upon  leaving  the  stomach,  the  greater  part  of 
the  protein,  carbohydrates,  and  all  the  fats  and  oils,  remain 
to  be  acted  upon. 

The  Stomach  as  a  Storehouse.  —  It  is  a  common  notion 
that  digestion  is  carried  on  chiefly  in  the  stomach.  Some 
physiologists  give  tables  stating  that  pork  requires  five  hours 
for  digestion,  fried  beef  four  hours,  roasted  beef  three  hours, 
apples  one  hour,  etc. ;  what  is  meant  is  that  it  requires  that 


The  Digestion  of  Food 


169 


length  of  time  for  these  foods  to  leave  the  stomach,  the  di- 
gestion being  far  from  complete.  Investigation  in  the  last 
few  years  shows  that  the  stomach  is  a  kind  of  storeroom  or 
antechamber  in  which  food  is  stored,  being  softened  and 
kept  free  from  germs  and  gradually  delivered  to  the  intestine. 

Of  the  thirty  or  more  feet  of  the  alimentary  canal,  the 
food,  upon  leaving  the  stomach,  has  traversed  about  two  feet. 
Of  the  fourteen  hours  required  for  digestion,  about  three  or 
four  hours  have  passed.  A  portion  of  the  starch  and  protein 
has  been  digested  and  a  small  amount  of  each  absorbed  by 
the  blood  vessels/  The  fats  have  not  yet  been  acted  upon. 

It  is  essential  that  the  part  performed  by  each  prior  organ 
should  be  well  performed,  for  this  determines  whether  the 
changes  in  the  food  in  the  next  organ  shall  be  easily  and  com- 
pletely accomplished.  If  the  food  is  thoroughly  masticated 
in  the  mouth  and  the  saliva  well  mixed  with  it,  this  alkaline 
condition  excites  the  flow  of  the  acid 
gastric  juice,  which  otherwise  would  be 
scanty.  If  the  gastric  juice  is  strong 
and  acts  freely  upon  the  food,  the 
acidity  of  the  food  as  it  leaves  the 
stomach  and  enters  the  small  intestine 
excites  the  flow  of  the  alkaline  intes- 
tinal juices. 

The  small  intestine.  —  When  the 
chyme  passes  the  pylorus,  it  enters  the 
small  intestine,  which  is  a  tube  about 
as  large  around  as  the  thumb,  and 
about  twenty  feet  long,  lying  coiled  in 
the  central  part  of  the  abdominal 

FIG.  113.  —  A  portion 

cavity.  The  first  part  of  it,  about  ten  Of  small  intestine  'cut 
inches  in  length,  is  called  the  duodenum  *  folds 


(from  a  word  meaning  twelve,  because 

its  length  is  twelve  fingers'  breadth).      The  mucous  and 

submucous   coats  of  the   small   intestine   are  wrinkled   by 


1 70 


Healthful  Living 


numerous  folds  which  are  crescent-shaped,  since  no  single 
fold  goes  entirely  around  the  tube  (Fig.  113).     The  folds 

are  so  numerous  that 
they  occupy  almost 
the  entire  inner  sur- 
face. The  small  in- 
testine is  the  chief 
organ  of  absorption 
as  well  as  of  diges- 
tion, and  the  absorb- 
ing surface  is  greatly 
increased  by  the 
folds.  On  and  be- 
tween the  wrinkles 
are  innumerable  tiny 
projections  called 
villi  *  (Fig.  114). 
Each  villus  contains 
a  loop  of  blood  vessel 
and  a  very  small 
lymphatic  called  a 
lacteal.  Since  the 

FIG.  114. —  To  show   the   structure  of   the        -ii-  thirklv 

wall  of  the  small  intestine,    v,  villi,  and  g,  glands     V11J  LK1^ 


of  the  mucous  membrane ;  c,  circular  muscle 
layer ;  I,  longitudinal  muscle  layer ;  p,  peri- 
toneum, or  serous  coat. 


placed  as  to  cover 
the  entire  mucous 
coat  of  the  intestine 
like  the  pile  on  a  piece  of  velvet,  the  absorbing  surface  is 
enormously  increased. 

The  Support  of  the  Intestine.  —  The  abdominal  cavity, 
or  the  portion  of  the  large  cavity  of  the  trunk  below  the 
diaphragm,  has,  like  the  thoracic  cavity,  a  lining  to  prevent 
friction.  This  membranous  lining  is  called  the  peritoneum, 
and  like  the  pleura,  it  is  double.  It  covers  up  the  wall  of 
the  cavity  all  around,  lining  it  like  a  thin  sheet,  until  it 
reaches  the  place  under  the  diaphragm  where  the  esophagus 


The  Digestion  of  Food 


171 


and  larger  blood  vessels  (aorta  and  vena  cava)  enter,  where 
it  is  reflected  and  courses  downward,  enveloping  the  stomach 
and  other  digestive  organs.  It  penetrates  between  them 
by  means  of  foldings  and  turnings,  thus  assisting  to  hold 
them  in  place.  The  largest  fold  of  all  is  called  the  great 
omentum  and  covers  the  small  intestine.  The  peritoneum 
surrounding  the  intestines  is  called  the  mesentery.  It  is  fan- 
shaped  and  its 
contracted  part  is 
attached  to  the 
spinal  column  for 
a  firm  support. 
The  alimentary 
canal,  beginning 
with  the  stomach, 
may  be  said, 
therefore,  to  have 
a  fourth  layer,  or 
covering,  the  peri- 
toneum. 

The  mesentery, 
which  surrounds 
the  intestines,  is 
attached  to  the 
back  wall  of  the 
abdominal  cav- 
ity. It  assists  in  holding  them  up  in  place.  This  support 
is  dependent  upon  and  is  assisted  by  the  abdominal  muscles 
in  front.  People  who  stand  with  a  relaxed,  protruding 
abdominal  wall,  lack  the  support  which  they  should  receive 
from  the  abdominal  muscles.  There  is  a  consequent  falling 
down  of  these  organs.  Such  a  condition  is  known  by  the 
name  viceroptosis  (dropping  of  the  viscera).  Constipation 
is  a  frequent  accompanying  condition,  due  to  interference 
with  the  circulation  in  the  intestines.  It  is  very  important, 


FIG.  115.  —  Showing  how  improper  posture  favors 
viceroptosis ;  the  mesentery  is  stretched  and  the 
circulation  to  the  loop  of  intestine  is  lessened. 


172  Healthful  Living 

therefore,  to  stand  and  walk  with  the  abdominal  wall  held 
in  (Figs.  115,  93)  and  to  exercise  these  muscles  by  partici- 
pating in  sports,  games,  athletics,  and  dancing. 

The  Digestive  Fluids.  —  The  digestive  fluids  that  enter 
the  small  intestines  are  the  pancreatic  juice  from  the 
pancreas,  the  intestinal  juice  from  the  small  intestinal 
glands  (Fig.  114),  and  the  bile  from  the  liver.  The  bile 
will  be  discussed  later  in  consideration  of  the  liver.  At 
present  we  will  study  the  other  two  juices  that  come  into 
the  small  intestine. 

(a)  The  pancreatic  juice.  —  The  pancreas,  or  sweet- 
bread, is  flat,  narrow,  and  about  six  inches  long.  It  lies  be- 
hind the  stomach,  and  tapers  toward  the  left,  ending  above 
the  left  kidney.  Its  shape  has  been  compared  to  a  dog's 
tongue,  and  like  the  root  of  the  tongue,  it  bends  downward 
at  its  broader  end,  where  its  duct  leaves  it  and  joins  the  bile 
duct  just  before  emptying  into  the  duodenum.  Its  internal 
structure  resembles  the  salivary  gland.  The  amount  of 
digestion  accomplished  in  the  small  intestine  exceeds  that 
in  any  other  division  of  the  canal,  and  the  pancreas  is  the 
most  active  and  powerful  of  all  the  glands.  Its  secretion, 
the  pancreatic  juice,  is  alkaline,  and  contains  three  enzymes, 
one  of  which  (amylopsin)  is  hardly  to  be  distinguished  from 
the  ptyalin  of  the  saliva,  and  continues  the  digestion  of  the 
starchy  food  ;  another  (enterokinase)  joins  with  the  trypsino- 
gen  of  the  intestinal  juice  and  forms  trypsin.  Trypsin  has 
an  action  similar  to  pepsin,  and  digests  protein;  while  the 
third  (lipase)  begins  the  digestion  of  an  important  class  of 
foods,  the  fats,  which  have  not  heretofore  come  in  contact 
with  a  digestive  fluid  that  could  act  upon  anything  more 
than  the  protein  envelopes  of  the  fat  cells. 

Two  definite  changes  occur  in  the  digestion  of  fat.  At 
an  early  stage  a  physical  change  occurs  and  the  fat  is  broken 
up  into  minute  globules.  This  favors  the  second  stage,  but 
in  itself  is  not  a  digestive  act,  because  they  are  only  in  a 


The  Digestion  of  Food  173 

state  of  fine  division  and  no  chemical  change  has  occurred. 
Such  globules,  floating  in  a  liquid,  form  what  is  called 
an  emulsion.  Milk  is  an  emulsion  of  cream.  It  is  the 
cream  in  sweet  milk  that  gives  it  the  white  appearance, 
for  the  globules  of  fat  reflect  the  light.  When  it  is 
churned  these  minute  particles  touch  and  adhere,  forming 
butter.  The  chemical  change  is  a  splitting  of  the  fat 
molecule  by  the  action  of  the  enzyme,  lipase,  producing 
fatty  acids  and  glycerin.  These  chemical  substances  are 
absorbed  by  the  intestinal  walls  and  passed  into  the  lacteals 
and  blood  stream. 

(6)  The  intestinal  juice.  —  Besides  the  two  large  glands, 
the  pancreas  and  liver,  there  are  a  great  number  of  very  small 
glands  (Fig.  114)  which  furnish  a  digestive  fluid  to  the  in- 
testine. The  intestinal  glands  are  scattered  throughout  the 
lining  membrane,  and  their  secretion  is  called  the  intestinal 
juice.  This  juice  contains  : 

(1)  Enterokinase,  which  activates*  the  trypsinogen  from 
the  pancreas,  forming  trypsiri. 

(2)  Erepsin,  which  splits  peptones  received  from  the  gastric 
digestion. 

(3)  Maltase,   invertase,   and    lactase,   which    split  disac- 
chrides  into   monosacchrides  as  described  under  the  para- 
graphs on  enzymes.     These  enzymes  are  often  called  invert- 
ing enzymes. 

Absorption  from  the  Small  Intestine.  —  The  fats  are 
absorbed  by  the  lymphatic  system.  Many  minute  lym- 
phatics called  lacteals  (Fig.  116)  are  found  in  the  villi  of 
the  intestines,  and  the  epithelial  cells  of  the  mucous  lining 
take  up  the  fat  and  transmit  it,  slightly  changed,  to  these 
lacteals,  which  unite  one  to  another  and  empty  into  the 
thoracic  duct.  The  thoracic  duct  empties  into  the  sub- 
clavian  veins  under  the  left  clavicle.  The  fats  thus  pass 
into  the  blood  stream. 

The  sugars  and  proteins  are  carried  by  the  portal  circu- 


i74 


Healthful  Living 


lation  to  the  liver.  In  this  organ  the  sugars  are  changed  to 
glucose  and  stored  until  needed  by  the  muscles.  The  protein 
is  passed  and  serves  to  build  new  tissue.  In  two  different 
ways,  therefore,  do  the  digested  food  elements  reach  the 
main  circulation.  This  provision  resembles  in  a  way  the 
means  of  travel  for  people  on  the  earth.  Some  go  by  one 


FIG.   116.  —  Diagram  of  villus,  with  enlarged  section  showing 
minute  structure. 

road  and  others  by  another.  Some  may  go  from  New  York 
to  Boston  by  rail  and  others  may  take  the  boat.  The  result 
of  the  journey  is  the  same  —  they  reach  Boston.  The 
mineral  matter  is  taken  into  the  blood  through  the  intestinal 
loops  and  apparently  in  the  same  way  that  we  account  for 
the  passage  of  the  digested  protein  and  carbohydrates.  This 
passage  of  these  elements  through  an  animal  membrane  at 


The  Digestion  of  Food 


Co/or? 


one  time  was  explained  according  to  the  law  of  osmosis,1 
but  it  is  now  believed  to  be  accomplished  by.  specific  se- 
cretory power  of  the  intestinal  cells.  In  other  words  be- 
cause the  intestinal  cells  are  intestinal  cells,  they  are  able  to 
do  this.  They  differ  in  this  respect  from  epithelial  cells 
in  other  parts  of  the  body. 

The  large  intestine  (or  colon).  —  The  large  intestine 
is  about  five  feet  long.  Its  walls  are  drawn  into  pouches, 
or  puckers,  by 
bands  of  muscles 
running  length- 
wise along  it. 
The  small  intes- 
tine joins  it  in  the 
lower  part  of  the 
abdomen  on  the 
right  side  (Fig. 
117).  The  junc- 
tion is  not  at  the 
end  of  the  large  in- 
testine but  above 
the  end.  The  part 
below  the  junc- 
tion is  called  the 
caecum.  Attached 
to  the  caecum  is  a 
small  tube  called 

the  vermiform  appendix.  Above  the  juncture  the  large 
intestine  is  called  the  colon.  The  ascending  colon  runs  up 
along  the  right  side  nearly  to  the  waist.  It  is  then  called 
the  transverse  colon,  and  it  comes  forward  and  crosses  just 

1  Osmosis.  —  "Whenever  two  solutions  of  different  concentrations  are 
separated  by  a  membrane  which  is  permeable  to  water,  there  will  be  a  flow 
of  water  through  the  membrane  in  the  direction  of  the  greater  concentra- 
tion." This  means  that  the  solution  that  has  the  greatest  concentration 
of  substances  in  it  will  exert  a  greater  force  on  the  weaker  solution. 


Cecum 


FIG.  117.  —  The  valve  between  the  small  and 
large  intestine ;  opening  of  small  intestine  and 
appendix.  Why  is  the  valve  called  ileocaecal? 


176 


Healthful  Living 


in  front  of  the  lower  line  of  the  stomach.  It  then  retreats 
to  the  rear  wall  and  passes  downward,  being  now  called  the 
descending  colon.  Near  the  left  hip  it  makes  a  double  bend 
called  the  sigmoid  flexure  (from  sigma,  the  Greek  letter  S). 
The  nine  inches  remaining  are  without  the  pouched  appear- 
ance, the  walls  being  smooth;  this  part  is  without  bends 
and  is  therefore  called  the  rectum  (from  Latin  rectus, 
straight) . 

Absorption  in  the  large  intestine  is  very  active  and  its 
contents  soon  lose  their  fluidity.     Although  it  is  mostly  the 

watery  portion 
that  is  absorbed, 
any  digested  food 
that  may  have 
escaped  absorp- 
tion in  the  small 
intestine  is  ab- 
sorbed by  the 
colon.  How  sav- 
ing and  econom- 
ical the  body  is ! 
All  the  undigested 
and  indigestible 
food  gathers  in 
the  sigmoid  flex- 
ure, and  descends 
at  intervals  into 
the  rectum,  from 
which  it  should  be 
evacuated  at  regu- 
lar intervals. 

Appendicitis.  — 
The  vermiform 
appendix  (worm- 
like  appendage) 


FIG.  118.  —  Abdominal  viscera  displayed  so  as 
to  show  the  portal  vein  carrying  the  blood  from 
the  viscera  to  the  liver.  /,  liver ;  g,  gall  bladder ; 
s,  stomach,  and  d,  duodenum  —  these  have  been 
divided  from  each  other  ;  p,  pancreas  ;  e,  spleen ; 
c,  large  intestine ;  i,  small  intestine.  The  trans- 
verse colon  and  part  of  the  small  intestine  have 
been  removed. 


The  Digestion  of  Food  177 

is  a  part  of  the  intestine  which  has  degenerated  in  man 
because  of  non-use.  At  one  time  it  served  a  purpose; 
today  it  serves  none.  Constipation,  causing  a  clogging  and 
congestion  of  the  appendix  favors  infection,  and  this  organ 
may  become  inflamed,  causing  appendicitis.  Appendicitis 
may  prove  fatal  if  the  operation  of  removing  the  diseased 
appendix  is  delayed  too  long. 

Constipation.  —  As  the  undigested  part  of  the  food  passes 
through  the  colon,  it  gradually  loses  its  water  and  becomes 
semi-solid.  This  is  waste  material  and  should  be  removed 
daily  by  a  regular  habit  of  emptying  the  bowel.  If  the 
bowel  is  allowed  to  remain  filled  with  its  waste  contents, 
there  occurs  absorption  of  poisons  from  this  mass  of  waste 
material.  These  poisons  taken  into  the  blood  (Fig.  118) 
and  carried  throughout  the  body,  cause  headache,  lassitude, 
weakness,  and  other  disorders. 

The  Use  of  Foods  in  Constipation.  —  There  are  many 
causes  of  constipation  but  it  is  generally  recognized  that  im- 
proper selection  of  food  may  play  an  important  part  in  the 
production  of  the  disturbance.  For  this  reason  it  is  of 
value  to  know  the  foods  that  are  laxative*  from  those  that 
are  constipating  and  to  use  this  knowledge  with  reference 
to  the  selection  of  proper  foods.  All  do  not  need  a  choice 
of  laxative  food  and  no  rule  can  be  made  for  all  people. 
Food  must  be  sele'cted  with  reference  to  the  individual's 

need. 

LAXATIVE  CONSTIPATING 

1.  Whole    wheat    and    graham       1.  White  flour  bread,  hot 

flour  products,  such  as  Pastry  made  with  lard  and 

bread,   crackers,   gems,  baking  powder  prepara- 

biscuits,  mush  tions 

Cake  and  custard  puddings 

2.  Fruits  such  as  prunes,  dried,       2.  Meats 

stewed    peaches,    dried,  Salted,  dried  and  smoked 

stewed  fresh  fruits  of  all  meats 

kinds  Poultry 

Salted  and  dried  fish 


178  Healthful  Living 

LAXATIVE  CONSTIPATING 

3.  Vegetables  3.  Vegetables 

Beets  Beans,  dried 

Celery 
Corn 

Cauliflower  4.  Cereals 

Onions  Rice 

Peas,  green  Farina 

Rhubarb 
Spinach 

Squash  .  5.  Miscellaneous 

Cheese 

4.  Meats  Cocoa  and  chocolate 

Wild     game,     as     rabbit,  Milk,  boiled 

duck,  pigeon,  quail,  deer,  Tea 

etc.  Coffee  substitutes  made  of 
Liver  wheat,  corn  and  barley 

5.  Oysters 

The  liver.  —  The  liver  is  a  large,  heavy  organ  situated 
on  the  right  side  of  the  body  in  the  abdominal  cavity  and 
lying  up  under  the  diaphragm. 

With  each  inspiration  the  liver  is  pushed  downward  and 
compressed  by  the  diaphragm,  the  blood  being  forced  out 
toward  the  heart,  and  it  fills  again  as  soon  as  the  breathing 
muscles  relax.  This  rhythmic  compression  is  of  great  im- 
portance in  keeping  the  blood  supply  to  the  liver  fresh  and 
pure,  and  preventing  congestion  in  it.  By  tight  clothing 
the  liver  is  often  forced  downward,  out  from  the  cover 
of  the  ribs,  and  becomes  permanently  displaced.  As  a 
result,  other  organs,  lower  in  the  abdomen  and  pelvis, 
are  crowded  upon  each  other  and  also  become  dis- 
placed. The  circulation  in  the  liver  is  diminished,  and 
hence  its  activity  is  decreased  and  the  complexion  loses  its 
freshness. 

Pain  in  the  right  side  after  a  rapid  walk  is  due  to  con- 
gestion of  the  liver  with  blood  from  the  legs.  What  would 
pain  in  the  left  side  be  due  to  ? 


The  Digestion  of  Food  179 

Anatomy  of  the  liver.  —  The  liver  is  the  largest  gland  in 
the  body.  It  is  of  a  reddish  brown  color  and  weighs  about 
three  and  one  half  pounds.  The  upper  and  front  surfaces 
of  the  liver  are  very  smooth  and  even.  The  under  surface 
is  very  irregular;  it  is  here  that  the  various  vessels  with 
which  this  active  organ  is  supplied  make  their  entrance  or 
exit.  Its  connecting  vessels,  beside  the  lymphatics,  are  the 
hepatic  artery  from  the  aorta,  bringing  pure  blood;  the 
portal  vein,  bringing  the  digested  food ;  the  hepatic  vein, 
carrying  impure  blood  to  the  vena  cava ;  and  the  bile  duct, 
carrying  the  bile  to  the  intestine.  The  bile  duct,  on  its  way 
from  the  liver,  gives  off  a  side  branch  to  the  gall  bladder. 
This  is  a  little  dark  green  bag,  in  which  the  bile  is  stored 
until  it  is  required  for  digestion. 

Circulation  through  the  Liver,  or  Portal  Circulation. — 
The  portal  vein  and  its  function  have  been  mentioned 
(Fig.  118).  When  it  enters  the  liver,  it  does  a  very  unusual 
thing ;  in  fact,  it  conducts  itself  as  no  other  vein  in  the  body 
does,  except  some  of  the  veins  in  the  kidneys.  It  subdivides 
into  capillaries.  Thus  the  portal  vein  (Latin,  porta,  a  gate, 
since  it  enters  under  a  kind  of  archway)  both  begins  and  ends 
in  capillaries,  for  it  begins  in  the  capillaries  of  the  digestive 
tract  and  ends  in  the  capillaries  of  the  liver.  After  these 
capillaries  have  passed  in  among  the  cells,  they  unite  again 
to  form  the  hepatic  veins,  which  go  directly  to  the  ascend- 
ing vena  cava.  There  is  another  large  blood  vessel  in  the 
portal  circulation.  This  is  the  hepatic  artery,  which  enters 
the  liver  directly  from  the  aorta  and  supplies  the  liver  cells 
with  arterial  blood  with  which  to  repair  themselves  and  carry 
on  their  work.  The  capillaries  from  this  artery  unite  with 
those  of  the  portal  vein  in  forming  the  hepatic  vein.  A 
cow's  liver,  cut  in  two,  shows  in  places  small  gaping  holes, 
which  are  branches  of  the  hepatic  vein. 

Microscopic  Structure.  —  If  you  examine  the  surface  of 
a  piece  of  liver  obtained  from  the  butcher,  you  will  find  it 


180  Healthful  Living 

to  be  of  a  dark  red  color,  and  mottled  over  with  little  areas, 
each  measuring  about  one  twentieth  of  an  inch  across.  These 
are  the  round  lobules  of  the  liver  arranged  around  a  branch 
of  the  hepatic  vein  (Fig.  119).  The  capillaries  of  the  portal 
vein  and  hepatic  artery  and  the  branches  of  the  bile  duct 
pass  between  these  cells.  Study  carefully  Figure  120,  which 
represents  a  segment  of  a  lobule.  When  you  understand 


FIG.  119.  —  Diagrammatic  representation  of  two  hepatic  lobules.  The 
left-hand  lobule  is  represented  with  the  intralobular  vein  cut  across  :  in 
the  right-hand  one  the  section  takes  the  course  of  the  intralobular  vein. 
p,  interlobular  branches  of  the  portal  vein ;  h,  intralobular  branches  of  the 
hepatic  veins ;  s,  sublobular  vein ;  c,  capillaries  of  the  lobules  passing  in- 
wards. The  arrows  indicate  the  direction  of  the  course  of  the  blood.  The 
liver  cells  are  represented  in  only  one  part  of  each  lobule.  Trace  the  blood 
through  these  veins  and  name  the  vessels. 

the  circulation  in  a  lobule,  you  will  understand  the  circula- 
tion in  the  entire  liver,  for  a  lobule  is  the  liver  in  miniature. 
Represent  a  lobule  by  a  wagon  wheel.  The  rim  corresponds 
to  the  capillaries  of  the  portal  vein  and  hepatic  artery  circu- 
lating around  the  lobule.  The  spokes  correspond  to  the 
two  kinds  of  capillaries  united  and  on  the  way  to  the  hepatic 
vein  in  the  hub,  which  will  take  the  blood  away  from  the 
liver.  Between  the  spokes  are  located  the  hard  working 
liver  cells  which  get  oxygen  and  food  from  the  capillaries 
in  the  spokes,  and  relieve  themselves  of  impurities  by  means 
of  the  finest  bile  ducts  and  lymphatic  ducts,  which  begin 
among  the  cells. 


The  Digestion  of  Food 


181 


Functions  of  the  liver.  —  These  cells  of  the  liver  have  three 
functions :  (1)  to  secrete  bile  for  digestion  of  food ;  (2)  to 
store  certain  food  elements  after  digestion,  and  (3)  to  ex- 
crete from  the  blood  certain  waste  substances. 

Secretion  Duties.  —  The  secretion  of  the  liver  is  the  bile. 
It  passes  from  the  liver  cells  in  a  common  duct  that  leads 
to  the  intestine  and  gall 
bladder.  When  the  duct 
is  filled,  the  bile  "  backs 
up  "  into  the  gall  bladder, 
where  it  is  stored  until 
food  is  eaten,  when  it 
enters  the  small  intestine 
close  to  the  stomach.  The 
bile  aids  in  the  emulsifica- 
tion  of  the  fats. 

The  bile  contains  an 
enzyme,  amylase,  which 
has  the  same  function  as 
the  ptyalin  of  the  saliva. 
It  digests  starch.  The  bile 
salts  dissolve  the  fat  acids, 
promoting  emulsification 
and  assisting  in  absorption 
of  fat. 

Storehouse  Duties.  - 
The  sugars  and  protein 
when  digested  are  carried  to  the  liver.  The  protein  passes 
through  and  goes  on  to  the  cells  of  the  body.  The  sugar 
remains  in  the  liver  until  needed. 

If  a  frog  be  dug  up  in  the  first  part  of  its  winter  sleep,  and 
its  liver  be  examined  under  the  microscope,  the  cells  will  be 
found  swollen  and  full  of  glycogen,  a  substance  stored  up 
for  the  winter  needs  of  the  frog.  It  is  a  carbohydrate  ma- 
terial resembling  starch  and  made  from  digested  sugar. 


FIG.  120.  —  Microscope,  high  power. 
Diagram  of  a  portion  of  a  lobule  of  the 
liver,  showing  the  blood  vessels  and  bile 
ducts  injected  with  fluid,  p,  interlobu- 
lar  branch  of  portal  vein  sending  capil- 
laries to  open  into  h,  intralobular  branch 
of  the  hepatic  vein  which  lies  in  the 
middle  of  the  lobule ;  b,  a  lymphatic  ; 
c,  branch  of  hepatic  artery ;  d,  branch 
of  bile  duct ;  into  this  (d)  open  the  ducts 
which  lie  between  the  liver  cells. 


182 


Healthful  Living 


The  liver  cells  of  a  frog  which  has  just  come  out  in  the  spring 
will  be  found  shrunken  and  containing  no  glycogen  (Fig.  121). 
If  a  starving  rabbit  be  killed  and  its  liver  cells  examined,  no 
glycogen  will  be  found,  but  the  liver  cells  of  a  rabbit  which 
has  recently  been  fed  on  turnips  will  be  full  of  glycogen.  If 
two  rabbits  be  well  fed,  one  kept  in  a  cage  and  the  other 
hunted  around  all  day,  much  glycogen  will  be  found  in  the 
liver  of  the  quiet  rabbit,  and  very  little  in  the  liver  of  the 

hunted  one.  The  gly- 
cogen stored  up  is  used 
during  muscular  work  or 
starvation. 

The  sugar  absorbed 
by  the  small  intestine 
reaches  the  liver  through 

FIG.  121.  —  A,  Liver  cells  of  dog  after  a  tne    POrtal    Vein.       It    is 

thirty-six  hours'  fast;  5,  also  fourteen  taken  Up  by  the  liver 
hours  after  a  full  meal  —  in  the  latter  case  -,-,  -,  -,  -,  •  , 

swollen  with  glycogen.  cells    and     changed     into 

granules  of  glycogen,  to 

be  turned  into  sugar  again  during  times  of  hunger  and  hard 
work.  Thus,  only  a  small  amount  of  sugar  is  allowed  to 
enter  the  circulation  at  one  time,  only  1^  ounces  in  every 
1000  ounces  of  arterial  blood.  If  more  than  this  quantity 
enters  the  blood,  sugar  passes  out  through  the  kidneys. 

Excretion  Duties.  —  The  excretory  function  of  the  liver 
is  important.  As  the  blood  containing  the  food  passes 
through  it,  waste  substances  in  the  blood  from  the  tissues, 
or  poisons  that  may  be  in  the  food,  are  destroyed  and  the 
products  resulting  from  the  destruction  are  sent  out  of  the 
body  by  either  of  two  routes ;  by  way  of  the  bile  duct  and 
alimentary  canal  or  by  way  of  the  blood  vessels  and  kidneys. 
All  the  blood  in  the  body  passes  through  it  once  every  three 
or  four  minutes,  and  as  it  passes  it  is  purified.  The  waste 
products  resulting  from  the  work  done  in  the  body  are  made 
more  soluble,  so  that  they  can  be  carried  through  the  kidneys. 


The  Digestion  of  Food  183 

The  yellow  color  of  the  bile  is  due  to  a  pigment  resulting 
from  the  destruction  in  the  liver  of  wornout  red  corpuscles. 
The  bile  is  partly  an  excretory  product,  but  such  is  the  econ- 
omy of  the  system  that  it  serves  to  aid  digestion,  and  to 
keep  the  alimentary  canal  in  an  aseptic  condition.  A  man 
could  not  smoke  were  it  not  for  the  liver.  This  organ  takes 
up  the  nicotine,  if  not  too  great  in  amount,  and  destroys  it. 
If  one  drinks  alcohol,  the  liver  endeavors  to  oxidize  it  and 
get  rid  of  it,  so  that  the  body  may  not  suffer  harm  and  in- 
jury from  it  and  usually  the  liver  of  a  habitual  drinker  is 
crippled  or  destroyed  by  its  long  struggle  with  alcohol. 

A  man  would  live  many  yea*  s  longer  than  he  does  if  he 
were  not  all  the  time  producing  waste  products  in  his  body 
by  his  ordinary  activities.  The  excretory  organs  are  taxed 
to  remove  them.  In  the  young  child  as  it  is  growing  and 
developing,  the  skin  is  so  active,  the  kidneys  are  so  healthy, 
and  the  liver  is  so  vigorous,  that  the  waste  is  all  removed  and 
the  blood  is  pure.  That  is  why  a  healthy  child  has  so  sweet 
a  breath,  such  bright  eyes,  and  so  fair  a  skin.  When  he 
becomes  older  it  is  different.  The  same  is  true  of  a  dog; 
the  puppy's  breath  is  pure,  its  body  is  clean,  so  that  it  may 
lie  in  a  lady's  lap  or  on  a  sofa  and  leave  no  unpleasant  odor. 
But  when  he  is  old,  the  dog  becomes  so  offensive  that  he 
has  to  be  driven  out  of  the  house.  The  strong  odor  results 
from  the  accumulation  of  waste  substances  in  the  body. 

Urea  is  the  chief  waste  product  which  results  from  the 
breaking  down  of  protein,  and  it  is  believed  that  the  nitroge- 
nous urea  is  formed  by  the  liver.  An  excess  of  protein, 
such  as  lean  meat  and  cheese,  in  the  diet,  produces  an  in- 
creased excretion  of  urea  through  the  kidneys.  It  is  ob- 
vious that  excess  of  food  and  lack  of  exercise  may  lead  to  the 
disturbance  of  liver  function.  Such  disturbance  may  be 
relieved  by  a  spare  diet  and  vigorous  exercise.  The  poor, 
overworked  liver  should  not  be  blamed,  however,  nor  the 
statement  made  that  "  the  liver  is  not  acting."  At  the  very 


184 


Healthful  Living 


•     The  Digestion  of  Food  185 

time  the  complaint  is  made,  the  skin  and  eyes  may  be  yellow, 
showing  the  presence  of  too  great  a  quantity  of  bile,  which  is 
a  product  of  the  activity  of  the  liver. 

Functional  disturbance  of  the  liver  may  result  from  three 
causes :  (1)  The  first  and  most  usual  form  is  caused  by 
fermentation  and  other  forms  of  indigestion,  and  by  the 
poisonous  products  therefrom  entering  the  blood.  (2)  Stop- 
page of  the  chief  bile  duct  because  of  congestion,  which  ex- 
tends to  it  from  the  stomach.  This  congestion  is  caused 
by  irritation  of  undigested  food;  (3)  The  liver  cells  and 
ducts  may  become  choked  up  from  excessive  food. 

The  waste  products  from  food  elements.  —  When  the 
foods  are  oxidized  in  the  body  there  are  several  products  of 
oxidation  called  waste  products.  The  starches  and  sugars, 
the  fats  and  oils,  when  oxidized,  give  rise  to  water  and  carbon 
dioxide.  The  protein  gives  rise  to  various  products,  of  which 
the  most  important  are  urea,  uric  acid,  and  creatin.  These 
are  excreted  by  the  kidneys.  There  are  also  found,  in  the 
excretion  of  the  kidneys,  small  quantities  of  phosphate  and 
sulphate  of  calcium,  sodium,  and  potassium.  Urea  is  a 
substance  of  great  importance,  as  it  is  the  most  abundant 
nitrogenous  waste  substance  produced  by  the  processes  of 
action  and  growth  in  the  cells  of  the  body.  '  Carbon  dioxide 
leaves  the  body  through  the  lungs,  and  water  leaves  it 
through  the  lungs,  kidneys,  and  skin. 

If  a  man  were  to  live  all  day  in  a  small  chamber  placed 
upon  very  delicate  platform  scales,  he  would  find  that  he 
lost  weight  every  second  of  his  existence  except  when  taking 
food,  and  more  rapidly  at  some  times  than  at  others,  the 
amount. of  loss  depending  upon  the  activity  of  his  body. 
The  loss  of  weight  occurs  through  the  excretions  which  the 
man  gives  off.  At  average  temperature  of  the  air  and  average 
activity  of  his  body,  the  day's  loss  to  be  replaced  by  food 
eaten,  water  drunk,  and  air  breathed,  would  be  about  as 
follows : 


i86  Healthful  Living 

From  the  large  intestine     ...        5  oz.  excrement 
From  the  skin .     .     .     ,     .     .     .       25  oz.  perspiration 

From  the  kidneys 50  oz.  excretion 

From  the  lungs 35  oz.  carbon  dioxide  and  water 

Total 115  oz. 

The  total  loss  is,  then,  nearly  8  pounds,  three  fourths  of 
which  is  water  (nearly  6  pounds) .  The  remainder,  except  the 
5  ounces  of  excrement,  consists  of  those  waste  materials 
(solid  or  gaseous)  which  result  from  the  breaking  down  of 
the  active  living  protoplasm  into  simple  chemical  sub- 
stances, through  the  process  of  oxidation.  This  amounts 
to  27^-  ounces  and  is  apportioned  as  follows :  perspiration, 
•J-  ounce  of  salts,  and  a  trace  of  urea ;  the  kidney  secretion, 
1  ounce  of  salts  and  1-J  ounces  of  urea ;  the  lungs,  25  ounces 
of  carbon  dioxide  gas. 

APPLIED   PHYSIOLOGY 

LABORATORY  EXERCISES 

Experiment  1.    To  study  the  intake  of  fluid  by  the  body  per  day. 

Material.  —  Coordinate  paper,  record  of  the  number  of  glasses 
of  fluid  taken. 

Method  and  observation.  —  Estimate  the  number  of  ounces 
of  fluid  taken  by  counting  the  number  of  glasses  of  water,  milk, 
soda,  etc.,  taken  in  one  day.  The  common  tumbler  or  glass  will 
hold  eight  ounces.  Continue  this  observation  for  one  week.  At 
the  end  of  that  time,  record  on  coordinate  paper  on  the  abscissa  the 
days,  and  on  the  ordinate  the  total  ounces  per  day.  Connect  the 
points  by  straight  lines.  This  will  give  a  graphic  representation 
of  the  fluid  intake  for  one  week. 

If  this  experiment  is  performed  in  the  warm  weather,  it  will 
be  interesting  to  carry  along  with  this  record  of  the  fluid  intake, 
the  average  temperature  of  the  atmosphere  on  each  day.  If  this 
is  done,  record  the  temperature  on  the  chart  and  observe  any  rela- 
tionship that  exists. 
Experiment  2.  To  test  food  material  for  starch. 

Material.  —  Cornstarch,  tincture  of  iodine,  and  test  tubes, 

Method  and  observation.  — 


The  Digestion  of  Food  187 

(a)  Mix  a  small  amount  of  starch  and  water  in  a  test  tube  to 
the  consistency  of  a  thin  paste.  Add  a  few  drops  of  iodine  to  the 
mixture.  What  is  the  result  ? 

(6)  Add  some  water  to  a  small  part  of  a  boiled  potato.     Mash 
the  potato  in  the  water.     Add  a  few  drops  of  iodine.     What  is  the 
result  ?     Iodine  gives  a  deep  purple  in  the  presence  of  starch. 
Experiment  3.   To  test  for  sugar  (glucose). 

Material.  —  Glucose,  the  Fehling  copper  and  the  Fehling  alka- 
line solutions,1  test  tubes,  and  Bunsen  flame  or  alcohol  lamp. 

Method  and  observation.  —  Dissolve  some  glucose  in  water  in 
a  test  tube.     To  this  solution  add  equal  parts  separately  of  the 
Fehling  solutions  and  heat  to  boiling.     The  presence  of  glucose  is 
determined  by  the  change  of  the  solution  to  a  brick  red. 
Experiment  4.    To  test  for  fats  and  oils. 

Material.  —  Nuts  or  animal  fats,  white  paper,  ether. 

Method  and  observation.  —  (a)  Rub  the  kernel  of  a  nut  with  the 
covering  removed  on  a  piece  of  paper.  Hold  the  paper  to  the 
light.  The  fat  changes  the  light  qualities  of  the  paper.  (6)  Mash 
the  kernel  of  a  nut  in  a  dish  and  add  ten  cubic  centimeters  of  ether. 
Break  up  the  kernel  thoroughly  and  allow  the  preparation  to  stand 
several  minutes.  Filter  and  save  the  nitrate,  allowing  it  to 
evaporate. 

Ether  extracts  oil  from  substances  and  on  evaporation  leaves 
the  oil. 
Experiment  5.   To  test  for  protein. 

Material.  —  White  of  egg  (raw),  nitric  acid,  ammonia,  caustic 
soda  or  potash,  dilute  copper  sulphate,  test  tubes. 

Method  and  observation  —  (a)  The  Xanthoproteic  reaction. 
Place  the  white  of  the  egg  in  a  test  tube  and  add  nitric  acid.  Heat 
gently  to  boiling.  Cool  and  add  ammonia.  If  protein  is  present, 
a  deep  yellow  color  will  appear  on  the  addition  of  the  ammonia. 
(6)  The  Biuret  reaction.  Place  the  white  of  an  egg  in  a  test  tube 
and  add  two  centimeters  of  the  caustic  soda.  Then  add  a  few 
drops  of  the  dilute  copper  sulphate  solution,  being  careful  to  avoid 
excess.  If  protein  is  present,  a  purple  color  will  appear.  A  blue 
color  without  any  red  is  a  negative  test. 

1  The  Fehling  copper  solution  is  made  by  adding  35  grams  of  copper 
sulphate  (CuSOO  to  500  c.c.  of  water;  the  alkaline  solution  by  adding  160 
grams  of  sodium  hydroxide  (Na(OH)2)  and  173  grams  of  Rochelle  salt  to 
500  c.c.  of  water. 


1 88  Healthful  Living 

GLOSSARY 

Absorption.  —  The  process  by  which  nourishing  material  is  taken 
up  by  the  body  through  the  mucous  membrane  of  the  ali- 
mentary tract. 

Activates.  —  To  make  active  and  to  induce  therein  activity. 

Alimentary  canal.  —  The  digestive  tract  or  canal  along  which 
passes  the  aliment  from  which  the  body  absorbs  nourishing 
material. 

Chyme.  —  The  partly  digested  food  as  it  passes  from  the  stomach 
into  the  small  intestine  to  be  converted  into  chyle.  From 
the  Greek  word,  chymos,  meaning  juice. 

Epiglottis.  —  A  small  leaflike  structure  above  the  glottis.  The 
glottis  is  the  name  given  to  the  upper  end  of  the  larynx. 

Hydrochloric  acid.  —  A  colorless,  corrosive  compound  (HC1).  It 
occurs  in  the  gastric  juice  in  .3  to  .5  per  cent. 

Laxative.  —  A  substance  which  stimulates  the  action  of  the  in- 
testines. It  acts  by  increasing  peristaltic  action. 

Neutralize.  —  To  render  inert,  incapable  of  further  action.  Acids 
neutralize  alkalis,  and  vice  versa. 

Peristalsis.  —  The  wavelike  contraction  that  passes  over  the 
intestines  and  stomach  due  to  the  contraction  of  the  circular 
and  longitudinal  muscle  fibers. 

Pharynx.  —  The  back  part  of  the  mouth.  The  cavity  from  which 
goes  the  air  through  the  larynx,  trachea,  and  bronchi  to  the 
lungs,  and  food  and  drink  through  the  esophagus  to  the 
stomach. 

Pylorus.  —  The  gateway  between  the  stomach  and  small  intes- 
tine. 

Rheumatism.  —  A  condition  in  the  body  caused  by  disease-pro- 
ducing organisms.  These  get  into  the  blood  and  attack  the 
membranes  of  the  joints  and  heart  valves.  The  entry  is 
most  often  made  through  the  cavities  of  teeth  or  infected 
tonsils.  The  disease  is  not  caused  by  uric  acid. 

Tonsil.  —  A  small  lymphatic  gland  on  each  side  of  the  mouth  at  the 
entrance  to  the  pharynx. 

Uvula.  —  The  tiplike  structure  hanging  down  from  the  margin 
of  the  soft  palate  at  the  margin  of  the  pharynx. 

Villus.  —  A  small  finger-like  projection  from  the  mucous  membrane 
of  the  small  intestine.  The  plural  form  is  villi. 


CHAPTER  XI 
THE    HYGIENE    OF   DIGESTION 

I.    Digestion,  and  Health. 
II.    Digestion  and  Environment. 

III.  Hobbies  about  Nutrition. 

Hot  water 
Raw  food 
No  condiments 
Vegetarianism 
No  breakfast 

IV.  Man's  Original  Food  Resources  and  How  They  Have  Been 

Enlarged. 

V.    Present-day  Sources  of  Food. 
Nuts 

Pods  or  legumes  Milk,  cheese,  and  eggs 

Fruits  Grains 

Meats  Vegetables 

VI.   Patent  Medicines. 
VII.    Shall  we  drink  water  at  meals? 
VIII.    General  Rules  Modified  by  Individual  Needs. 
Indigestion 

Two  ways  out  of  a  difficulty 
IX.    Cooking. 
Meats 
Cereals 
Vegetables 
Eggs 

X.    The  Fireless  Cooker. 
XI.    Times  for  Eating. 

Exercise  in  relation  to  eating 


Digestion  and  health.  —  A  wit  once  said  that  if  he  had 
been  consulted  at  the  creation  of  the  world,  he  would  have 

189 


190  Healthful  Living 

made  good  health  "  catching  "  instead  of  disease.  Obser- 
vations show  that  happiness,  industry,  health,  faith,  and 
other  of  the  strong  elements  that  make  up  life  are  more 
contagious  than  misery,  idleness,  sickness,  worry,  and  the 
other  weak  elements  that  tend  to  destroy  life.  Fear  causes 
a  tightening  of  the  muscles  and  a  waste  of  energy,  as  well  as 
oppressed  breathing  and  a  lack  of  oxygen.  Courage  brings 
calm,  full  breathing  which  purifies  the  blood,  and  a  steady 
and  economical  use  of  the  muscles  which  saves  the  vital 
energy.  A  brave  and  cheerful  visitor  can  inspire  an  ailing 
friend  and  assist  in  his  recovery.  A  happy,  unselfish  teacher 
or  pupil  can  dispel  worry  or  gloom,  and  impart  strength  and 
increased  power  for  work  to  the  whole  school.  The  body 
tends  to  health  and  not  to  disease.  The  dyspeptics  *  that  we 
see  have  been  able  to  break  down  their  health  only  after 
long-continued  attacks  upon  it,  and  outrages  many  times 
repeated.  Fresh  air  brings  health,  and  forces  its  way  into 
the  home  to  bring  it,  but  the  dyspeptic  made  every  attempt 
to  keep  it  out.  Sunshine  brings  health,  but  he  shut  himself 
up  in  a  stuffy  ill-lighted  office,  a  slave  to  dollars  or  to  fame. 
He  curtained  the  sunshine  out  from  the  home  to  protect  the 
carpets  and  hangings  from  fading.  Exercise  brings  health, 
but  the  promptings  to  stir  about,  to  walk,  to  run,  or  to  work 
with  the  hands,  were  repressed  until  the  impulses  ceased. 
When  activity  was  lessened,  the  appetite  for  food  diminished, 
but  instead  of  following  the  prompting  of  nature,  he  sprinkled 
more  salt  and  pepper  and  other  condiments  upon  the  food, 
that  he  might  eat  with  an  unnatural  appetite. 

By  keeping  up  these  artificial  ways  for  months  and  years, 
he  at  last  succeeded  in  breaking  down  his  health.  It  took 
more  perseverance  to  weaken  the  body  than  it  will  take  to 
make  it  strong  again.  There  must  be  a  return  to  sensible 
ways  of  living  with  a  reasonable  trust  in  the  inherent  tend- 
ency of  the  cells  to  restore  soundness  when  given  a  chance. 
If,  however,  he  commits  the  folly  of  thinking  that  months 


The  Hygiene  of  Digestion  191 

are  not  needed  for  recovery,  but  that  disease  brought  on  by 
months  or  years  of  wrong  living  can  be  cured  in  a  few  days 
by  taking  magical  drugs  and  patent  medicines,  he  will  in- 
jure himself  still  more  and  probably  lose  his  chance  of  re- 
covering sound  health. 

Digestion  and  environment.  —  It  is  known  that  the  race 
originally  did  not  dwell  in  houses,  and  had  few  tools  or  cook- 
ing utensils.  Man  probably  first  lived  in  the  tropics  and 
subsisted  upon  the  fruits  which  ripened  in  the  never-ending 
summer,  and,  as  he  migrated  to  the  colder  climates,  sub- 
sisted upon  the  results  of  the  chase.  That  individual  who 
refused  to  peel  his  apples  because,  as  he  said,  Adam  had  no 
pocket  knife,  and  slept  with  his  windows  open  because  Adam 
had  no  house,  had  a  right  principle  in  view.  If  his  teeth 
were  as  sound  as  the  teeth  of  primitive  man,  and  his  habit 
of  mastication  as  thorough,  fruit  skins  would  be  an  aid  to 
digestion. 

Man  possesses  a  stomach  intended  to  digest  the  pure  food 
of  the  forest,  obtained  by  activity  in  the  open  air.  If  a  man 
eats  plain  food  and  leads  an  active  life,  his  appetite  is  a 
perfect  guide.  If  he  does  not,  it  is  unsafe  to  trust  to  the 
appetite  alone,  for  the  reason  that  he  lives  under  conditions 
unlike  those  for  which  this  instinct  was  built  up.  A  cow's 
appetite  is  a  certain  guide  to  her  among  poisonous  plants 
and  berries,  yet  she  will  eat  a  bucket  of  paint  and  harm  her- 
self ;  the  bucket  of  paint  is  beyond  the  range  of  her  inherited 
habits.  Even  if  man's  instincts  had  their  early  strength, 
they  could  hardly  guide  him  among  the  many  food  concoc- 
tions and  preparations  undreamed  of  by  primitive  man.  We 
can  train  our  taste  into  wrong  ways,  and  we  can  likewise 
train  it  into  right  ways  and  into  liking  food  that  we  know 
is  wholesome. 

It  is  found  that  returning  to  natural  habits  by  going  on 
camping,  hunting,  and  fishing  trips  is  one  of  the  most  ef- 
fective hygienic  measures  for  the  restoration  of  health. 


192  Healthful  Living 

Hobbies  about  nutrition.  —  The  subject  of  food  and  di- 
gestion is  a  more  complicated  one  than  that  of  exercise  or 
breathing,  and  common  sense  is  required  to  master  it. 
Therefore,  more  persons  fail  to  master  it,  and  allow  their 
minds  to  come  to  rest  on  some  one  fact  or  view  of  the  subject 
and  so  become'  extremists. 

Hot  water.  —  Some  would  cure  every  digestive  ill  by 
means  of  water.  Their  belief  is  "  water  internally,  ex- 
ternally, and  eternally."  They  sometimes  drink  it  as  hot 
as  it  can  be  borne,  yet  hot  water  is  very  relaxing  to  the  walls 
of  the  stomach  and  weakens  the  flow  of  the  gastric  juice. 
This  extreme  belief  arose  from  the  fact  that  hot  water  re- 
moves the  mucus  from  a  stomach  suffering  from  catarrh  (or 
congestion*)  and  diminishes  the  activity  of  the  gastric  glands 
if  too  much  acid  is  being  secreted. 

Raw  food.  —  Some  persons  have  a  fad  called  the  raw  food 
doctrine,  and  eat  no  cooked  foods.  They  should  consider 
that  man's  digestive  organs  are  not  as  vigorous  now  as  they 
were  ages  ago,  before  he  learned  the  use  of  fire.  This  fad 
is  a  reaction  from  bad  cooking.  Cooked  vegetables  are  more 
likely  to  ferment  in  a  weak  stomach  than  raw  vegetables. 
The  thorough  chewing  required  by  raw  food  is  an  advantage 
to  digestion. 

No  condiments.  —  Some  persons  will  not  have  condiments 
or  any  kind  of  seasoning,  not  even  salt,  in  their  foods.  This 
is  because  many  cooks  destroy  the  natural  flavors  of  the 
food  by  bad  cookery  and  hide  the  result  by  high  seasoning. 
There  are  many  delicate  and  delicious  flavors  of  grains, 
fruits,  and  fresh  vegetables  that  a  natural  appetite  takes 
pleasure  in ;  but  because  of  long  use  of  badly  cooked  and 
highly  seasoned  foods  the  sense  of  taste  in  many  persons 
has  become  so  depraved  and  dull  that  they  have  only  five 
kinds  of  taste  left :  the  taste  for  grease,  salt,  pepper,  vinegar, 
and  sugar.  Their  dull  nerves  require  everything  to  be  very 
salty  or  peppery  or  sweet  or  greasy  or  sour. 


The  Hygiene  of  Digestion  193 

Vegetarianism.  —  Some  people  have  an  aversion  to  eating 
animal  food  but  will  eat  vegetable  food  only.  In  develop- 
ment, animal  and  plant  came  from  the  same  source  and  life 
in  each  differs  only  in  degree.  It  is  known  that  animal 
protein  is  absolutely  necessary  for  health.  Pellagra,  a  very 
serious  disease  producing  marked  changes  in  the  nervous 
system,  results  from  the  exclusion  of  certain  essential  animal 
food  elements.  Most  "  vegetarians  "  are  not  vegetarians 
at  all.  They  are  only  "  no  meat  eaters/'  because  they  eat 
eggs,  butter,  and  milk  and  these  are  all  animal  food. 

Those  with  whom  meat  does  not  agree,  or  who  for  humane 
scruples,  or  other  causes,  adopt  a  vegetarian  diet,  sometimes 
fall  into  serious  error.  If  fruits  and  nuts  are  not  freely  used, 
but  the  diet  is  confined  to  grains  and  green  vegetables,  a 
large  excess  of  starch  is  consumed,  and  the  diet  is  very  bulky 
in  spite  of  the  fact  that  it  is  greatly  lacking  in  fat  and  protein. 
Persons  who  do  not  eat  meat  should  replace  the  protein  of 
meat  with  that  of  nuts,  cheese,  beans,  and  peas,  and  employ 
fat  in  the  form  of  nuts,  cream,  milk,  eggs,  and  butter. 

No  breakfast.  —  Those  who  eat  no  breakfast,  make  up 
in  amount  at  the  other  two  meals.  Instead  of  taking  three 
meals  to  eat  the  food  necessary  for  them,  they  eat  it  in  two. 
It  is  more  hygienic  to  eat  three  small  meals  than  two  large 
ones.  Moreover,  one  can  do  better  work  in  the  morning  after 
a  good  breakfast.  A  good  breakfast  might  include  prunes, 
milk,  rolls,  and  a  boiled  egg.  The  practice  of  eating  some 
mushy  cereal  loaded  with  fruit  and  covered  with  cream  and 
sugar  is  not  to  be  recommended.  Cooked  cereal,  such  as 
oatmeal,  eaten  with  a  little  butter  on  it  is  a  desirable  form 
of  breakfast  food. 

Man's  original  food  resources  and  how  they  have  been 
enlarged.  —  Cuvier,  Owen,  Huxley,  and  other  comparative 
anatomists  agree  that  man  was  originally  frugivorous;  he 
ate  tree  fruit,  both  nuts  and  fleshy  fruits.  Tree  fruits  con- 
tain all  the  four  chemical  classes  of  foods,  —  proteins,  fats, 


194  Healthful  Living 

carbohydrates,  and  minerals.  The  present  sources  of  his 
food,  besides  the  original  nuts  and  fruits,  are  flesh,  grains, 
herbs,  and  he  has  added  them  to  his  dietary  probably  in  the 
order  named  above.  In  the  warm  regions  of  the  earth,  the 
banana,  plantain,  mango,  orange,  and  cocoanut  trees  bear 
their  luscious  fruit  the  year  round.  But  the  multiplication 
of  the  race  and  perhaps  times  of  drought  and  famine  led 
man  to  use  the  food  stored  up  in  the  flesh  of  other  animals 
which  had  obtained  it  from  grass  and  herbs.  This  necessity 
doubly  increased  with  migration  to  colder  climates.  In  the 
frigid  zones  the  inhabitants  live  very  largely  on  animal  food. 
They  consume  immense  quantities  of  blubber,  or  the  fat  of 
certain  animals,  such  as  the  whale,  the  walrus,  and  the  seal. 
This  kind  of  diet,  by  sustaining  the  necessary  bodily  heat, 
enables  these  people  to  withstand  the  intense  cold  to  which 
they  are  subjected. 

Grains  in  their  natural  state  are  too  small  and  collecting 
them  was  too  tedious  before  the  time  of  that  long-forgotten 
genius  who  first  thought  of  cultivating  them  in  order  to  im- 
prove them.  Fruits  and  grains  belong  to  the  seed  part 
of  the  plant.  The  coarser  woody  leaves  and  stem  and  roots 
were  probably  not  added  to  man's  food  until  the  art  of  cook- 
ing was  much  advanced.  The  degree  of  digestibility  seems 
to  coincide  in  most  persons  with  the  order  of  adoption  of  the 
classes  of  foods  by  the  race.  If  one  leads  a  sedentary  life, 
or  his  digestion  becomes  impaired,  the  weedy,  fibrous  vege- 
tables should  be  the  first  to  be  discarded  from  the  diet,  while 
flesh  and  fruits  seem  to  furnish  the  main  substance  for  in- 
valids even  after  grains  and  starches  prove  hard  to  digest. 

Present-day  sources  of  food.  —  We  have  learned  that 
man's  digestive  tract  has  developed  with  reference  to  plain 
food  gathered  by  his  own  physical  efforts.  Man's  food  to-day 
both  in  its  form  and  its  method  of  production  has  under- 
gone remarkable  changes.  Many  articles  are  brought  from 
lands  far  away  and  land  transportation  makes  it  very  easy 


The  Hygiene  of  Digestion  195 

to  eat  in  Maine  what  has  been  grown  in  California.  The 
city  man  may  buy  all  his  food  in  a  shop  and  never  in  all  his 
life  produce  actually  one  article  of  food.  Of  course,  he  pro- 
duces in  other  ways.  It  is  necessary  that  he  make  up  in 
other  ways  for  the  lack  of  physical  exercise  that  is  one  of  the 
advantages  gained  from  tilling  the  ground. 

Nuts.  —  Nuts  are  the  most  concentrated  and  nutritious 
of  all  foods.  Beefsteak  is  three  fourths  water,  while  nuts 
are  less  than  one  fourth  water.  Nuts  are  how  many  times 
as  nutritious  as  beefsteak?  This  refers  to  the  nut  "meats  " 
or  kernels.  Nuts  may  be  said  to  consist  of  one  half  fat, 
one  fourth  protein,  and  the  remaining  one  fourth,  water 
and  mineral.  The  fat,  unlike  that  of  butter,  oil,  and  fat 
meat,  is  emulsified*  in  nuts,  and  does  not  need  to  be 
divided  up  before  absorption  by  the  lacteals  in  the  small  in- 
testine. Their  density  encourages  the  habit  of  thorough 
chewing.  Nuts  are  made  up  of  little  cells,  each  of  which 
has  its  proportion  of  proteins,  fat,  and  dextrin,*  a  kind  of 
sugar.  The  small  boy  climbs  the  tree  and  gathers  the  nuts, 
cracks  and  eats  them,  and  digests  them  thoroughly.  The 
man  stays  in  his  office,  has  some  one  else  to  gather  them, 
masticates  less  thoroughly,  and  he  may  find  them  less  di- 
gestible, especially  if  he  always  eats  a  full  meal  before  tak- 
ing the  nuts.  Green  or  rancid  nuts  are  not  digestible.  Nuts 
should  be  eaten  during  the  meal  the  same  as  meat.  They 
are  not  easily  digestible  raw.  Persons  who  usually  eat  nuts 
after  they  have  already  eaten  too  much,  consider  them  very 
indigestible.  They  are  not  digestible  if  eaten  between  meals, 
or  if  not  thoroughly  chewed. 

Pods  or  legumes.  —  Pods  or  legumes  resemble  nuts  very 
closely  in  chemical  composition,  but  they  require  long  and 
thorough  cooking.  Their  seed  coats,  or  hulls,  consist  of 
cellulose*  or  woody  fiber,  which  may  well  be  removed.  The 
hulls  can  be  loosened  by  soaking  them  in  cold  water  before 
they  are  cooked.  Beans  and  peas  have  been  called  the  lean 


196  Healthful  Living 

meat  of  the  vegetable  kingdom,  and  they  contain  a  high 
percentage  of  protein. 

Fruits.  —  Fruits  have  four  important  advantages : 
(1)  Their  agreeable  flavors  are  a  natural  and  healthy  stimulus 
to  the  digestion.  (2)  They  contain  vegetable  acids  (either 
citric,  malic,  or  tartaric)  that  are  perfect  germicides,*  and  are 
of  value  in  purifying  the  alimentary  canal.  (Fruits  have 
almost  no  protein.)  (3)  They  contain  very  valuable  mineral 
salts  that  are  of  highest  use  to  the  blood  and  tissues.  (4)  The 
carbohydrate  in  ripe  fruits  is  all  in  the  form  of  levulose  or 
fruit  sugar,  which  is  absorbed  without  digestion.  With 
these  advantages  there  is  the  disadvantage  that  fruits  are 
largely  water,  so  that  the  nutriment  they  contain  is  very 
scant,  except  in  the  case  of  grapes,  bananas,  and  olives. 

The  proverb  that  fruit  is  golden  at  breakfast,  silver  at 
noon,  and  lead  at  night,  is  not  true.  Fruit  is  golden  at  all 
times,  if  it  is  sound  and  ripe,  and  if  the  stomach  is  not  already 
filled  with  food.  Fruit  juices  are  valuable  as  restoratives 
to  health,  since  they  tax  the  digestive  organs  very  little  and 
are  quickly  assimilated.  Since  germs  will  not  grow  in  fruit 
juices,  a  fruit  diet  for  several  meals  will  disinfect  the  ali- 
mentary canal  and  ward  off  a  "  bilious  "  attack.  Juicy 
apples,  pears,  lemonade,  orangeade,  pomegranateade,  ripe 
peaches,  etc.,  are  pleasanter  than  medicines. 

Meat.  —  Protein  is  the  principal  food  substance  in  meat. 
Beef  contains  the  largest  amount  among  the  common  meats, 
and  pork  the  least.  The  fat  of  meat  is  also  of  great  impor- 
tance :  fat  is  abundant  in  pork.  Meat  that  is  salted  and 
smoked,  or  dried,  or  prepared  in  any  way  so  that  germs  will 
not  grow  in  it,  can  be  kept  for  a  long  time,  but  its  digesti- 
bility is  greatly  impaired.  This  is  because  its  fibers  have 
been  hardened  so  that  the  gastric  juice  cannot  readily  pene- 
trate them.  Meat  which  has  much  connective  tissue  is 
tough;  the  most  tender  and  digestible  of  meats  consist 
almost  wholly  of  muscular  tissue  and  fat. 


The  Hygiene  of  Digestion  197 

Experiments  show  that  ordinarily  one  fifth  of  the  protein 
in  vegetable  food  passes  through  the  intestine  undigested 
and  unabsorbed,  and  is  thus  wasted,  while  only  one  thirtieth 
of  the  protein  in  meat  escapes  digestion.  A  pound  of  fat 
requires  three  times  as  much  oxygen  in  its  oxidation  as  a 
pound  of  sugar,  and  therefore  yields  three  times  the  heat  and 
energy.  The  digestibility  of  fat  is  increased  by  the  fact  that 
it  ferments  with  difficulty,  while  sugar  and  starch  ferment 
more  easily.  Meat  should  be  thoroughly  cooked  to  avoid  the 
danger  of  diseases  from  Trichina  spiralis  and  other  parasites. 

Meat  Extracts.  —  Researches  concerning  the  nutritive 
value  of  meat  extracts  show  that  in  none  of  them  is  a  large 
quantity  of  food  concentrated  in  a  small  bulk  as  the  public 
is  led  to  believe.  A  glass  of  milk  contains  far  more  nourish- 
ment than  a  cup  of  beef  tea.  The  best  way  to  get  the  nour- 
ishment out  of  a  steak  is  to  eat  it.  The  beef  extract  contains 
but  a  fraction  of  the  protein  in  beef,  and  all  of  the  nitrogenous 
waste  material  allied  to  urea.  The  most  nutritious  part  of 
the  beef  is  not  soluble,  but  the  excretory  part  of  the  meat 
is  soluble,  and  this  is  found  in  the  beef  tea  or  beef  extract. 
This  extract  throws  work  upon  the  kidneys  and  is  harmful. 
The  part  of  the  beef  that  has  most  value  is  thrown  away  in 
making  the  extract.  Many  lives  are  no  doubt  annually 
sacrificed  by  starvation  through  the  popular  faith  in  beef 
tea  as  a  concentrated  and  nourishing  food.  Beef  tea  and 
meat  juice  can  be  used  as  flavoring  agents  with  other  food 
since  they  stimulate  the  secretion  of  pepsin,  but  they  should 
not  be  regarded  as  real  food. 

By  drying  meat  it  can  be  reduced  to  one  fourth  its  weight 
(since  it  is  three  fourths  water).  Thus  100  pounds  of  beef 
can  be  reduced  to  25  pounds  and  sold  in  a  form  useful  to 
travelers.  The  meat  will  keep  fresh  as  long  as  it  is  kept  dry. 
Water  is  added  to  the  meat  when  it  is  cooked. 

Milk,  cheese,  and  eggs.  —  Cow's  milk  is  suited  for  calves, 
and  was  intended  to  be  obtained  by  sucking  and  to  be  swal- 


1 98  Healthful  Living 

lowed  gradually.  It  does  not  contain  the  right  proportion 
of  food  elements  for  infants  and,  therefore,  must  be  modified 
when  fed  to  infants.  The  casein  or  protein  part  is  coagu- 
lated in  flakes  by  the  rennin,  and  when  a  child  vomits  coagu- 
lated milk,  it  does  not  mean  that  it  is  suffering  from  indi- 
gestion, although  it  may  sometimes  mean  that  it  is  being 
overfed.  The  tendency  of  milk  to  produce  constipation  in 
some  persons  may  be  explained  as  follows :  when  adults 
drink  sweet  milk  rapidly,  especially  toward  the  end  of  the 
meal,  when  much  acid  is  present  in  the  stomach,  the  acid 
coagulates  the  casein  into  large  lumps  of  curd,  which  may 
seriously  disturb  the  digestion,  for  milk  was  not  intended 'to 
be  drunk  rapidly.  Heat  retards  the  production  of  acid  in 
the  gastric  juice  and  increases  the  secretion  of  rennin.  If 
taken  before  meals,  hot  and  slowly,  milk  will  agree  with 
those  who  have  found  it  to  produce  indigestion.  Butter- 
milk is  one  of  the  most  digestible  of  foods. 

Cheese  is  a  concentrated  food,  and  is  one  of  the  cheapest 
although  not  one  of  the  most  digestible  forms  of  protein. 

Eggs  are  valuable  food  and  in  proportion  to  their  value 
are  cheaper  than  meat.  They  are  very  digestible  when 
properly  cooked.  Eggs  should  not  be  fried  nor  boiled  hard. 

Grains.  —  Nearly  all  the  starch  of  our  food  is  supplied 
by  grains.  They  also  contain  from  8  to  15  per  cent  of  a 
protein  called  gluten.  The  chief  grains  are  wheat,  oats, 
barley,  corn,  rice,  buckwheat.  The  more  of  gluten  there  is 
in  grain,  the  more  gluey  or  sticky  its  flour  will  be.  Sticky 
flour  will  retain  the  bubbles  of  gas  formed  from  baking- 
powders  or  by  the  growth  of  the  yeast  plant.  Wheat  has 
much  gluten,  and  its  flour  makes  very  light  bread.  Corn 
meal  has  not  enough  gluten  to  make  it  very  sticky,  and  corn 
bread  will  not  rise  well.  Corn  contains  more  fat  than  any 
other  grain,  yellow  corn  containing  more  fat  than  white  corn. 
Wheat  is  richer  in  starch  and  protein  than  any  other  grain. 
If  cooked  several  hours,  the  starch  of  grains  is  so  thoroughly 


The  Hygiene  of  Digestion  199 

dextrinized  that  it  is  changed  to  sugar  almost  instantly 
when  brought  in  contact  with  the  saliva.  Grains  may  be 
cooked  during  the  preceding  meal  and  the  cooking  finished 
in  preparing  the  meal  at  which  they  are  to  be  eaten.  If 
oatmeal  and  other  mushes  are  sticky,  it  shows  the  presence 
of  half -cooked  starch.  Rice  and  oatmeal  may  be  first 
browned  in  the  oven  and  afterward  steamed.  Toast  and 
brown  crust  are  almost  as  digestible  as  ripe  fruit  and  may 
be  eaten  by  invalids. 

Three  Kinds  of  Flour.  —  There  are  three  ways  of  grinding 
wheat  to  make  flour :  (1)  Using  the  whole  grain  and  the 
husk  which  incloses  the  grain.  This  makes  graham  flour. 
(2)  By  using  the  whole  of  the  grain.  This  makes  whole 
wheat  flour.  (3)  By  rejecting  the  outer  and  darker  portion 
of  the  grain,  thus  losing  part  of  the  gluten  and  retaining  all 
of  the  starch.  This  makes  the  ordinary  flour. 

Graham  flour  is  most  stimulating  to  peristalsis  in  the  canal. 
Its  large  amount  of  waste  matter  furnishes  something  for 
the  intestine  to  contract  upon,  and  thus  sweep  all  waste 
matter  on  and  out  of  the  body,  contributing  to  the  cleanliness 
of  the  canal.  It  sometimes  causes  congestion  in  irritable 
stomachs.  Sometimes  flour  which  is  merely  dark  with  dirt 
is  sold  for  graham  flour.  The  whole  wheat  flour  is  stimu- 
lating to  the  canal  but  is  not  irritating. 

White  flour  is  used  more  extensively  because  it  makes  white 
bread.  This  is  judging  the  food  by  its  appearance  and  not 
by  its  food  value.  It  is  believed  by  some  that  the  whole 
wheat  flour  is  more  desirable  as  it  contains  salts,  food  ele- 
ments, and  waste  material  that  are  very  important.  Nations 
in  time  of  war,  when  economy  is  necessary,  use  the  whole  of 
the  wheat  in  the  milling  of  flour.  Nations  in  time  of  peace 
and  plenty  use  white  flour.  Nations  at  peace  should  not  be 
wasteful,  and,  moreover,  they  should  use  at  all  times  foods 
which  will  make  the  healthiest  and  most  efficient  citizens. 

In  the  Great  War,  Germany,  on  account  of  the  shortage 


soo  Healthful  Living 

of  wheat,  was  compelled  to  use  other  cereals  and  even  potatoes 
in  the  making  of  flour.  As  early  as  December  1,  1914,  the 
Bundesrat  issued  a  decree  that  no  bread  should  be  baked 
of  pure  wheat  flour.  The  war  flour  prescribed  "  must  con- 
tain at  least  ten  parts,  by  weight,  of  rye  flour  to  ninety  parts 
of  wheat  flour.  Rye  flour  must  contain  at  least  five  parts 
potato  flour  to  ninety-five  parts  of  rye  flour.  The  baker 
may  increase  the  portion  of  potato  flour,  but  bread  with 
more  than  five  parts  potato  flour  must  be  marked  with  the 
letter  "K"  (Kartoffel,  potato).  If  there  are  more  than 
twenty  parts  potato  flour,  the  figure  must  be  added  to  the 
"  K."  The  term  bread  includes  loaves,  rolls,  etc." 

Vegetables.  —  Root  vegetables  and  tubers,  such  as  potatoes, 
sweet  potatoes,  and  turnips,  contain  a  small  percentage  of 
starch.  But  vegetables  in  general  consist  almost  entirely 
of  water  and  woody  fiber  (cellulose).  This  is  especially 
true  of  green  vegetables,  or  those  which  consist  of  the  leafy 
part  of  the  plant.  But  green  vegetables  contain  an  iron- 
bearing  albumin,  which  is  of  great  value  to  the  blood  and 
tissues.  This  form  of  albumin  is  easily  destroyed  in  the 
intestine  before  it  reaches  the  blood,  if  fermentation  takes 
place.  As  some  leafy  vegetables  are  more  likely  to  ferment 
if  cooked,  there  is  an  advantage  in  eating  them  raw.  Iron 
and  valuable  mineral  salts  are  thus  obtained. 

Cellulose.  —  Cellulose  has  the  same  chemical  composition 
as  starch.  It  forms  the  cell  walls  and  woody  fibers  of  plants, 
and  is  hardly  digested  at  all  by  man ;  hence,  starch  requires 
cooking  to  burst  the  cellulose  envelopes  of  the  starch  grains. 
Cellulose  and  water  are  the  chief  constituents  of  grass,  and 
of  greens,  cabbage,  and  other  fibrous  vegetables.  It  forms 
the  fibers  in  watermelons,  which  also  contain  cane  sugar,  the 
sweetest  of  the  sugars.  The  woody  skins  of  beans  and  peas 
are  cellulose.  Hence,  many  find  the  legumes  more  digestible 
in  a  pure*e,  or  cooked  with  the  skins  removed.  Cellulose  is 
the  natural  stimulant  to  peristalsis  and  activity  of  the  canal. 


The  Hygiene  of  Digestion  201 

Cattle  digest  cellulose,  and  with  them  it  takes  the  place  of 
starch. 

Patent  medicines.  —  There  are  a  considerable  number  of 
people  who  violate  laws  of  health  and  then  seek  to  escape 
from  the  results  by  taking  a  pill  or  a  tonic*.  The  digestion 
of  food  is  not  a  mysterious  act  and  it  will  proceed  in  a  satis- 
factory manner,  if  simple  rules  of  living  are  adhered  to. 
Errors  in  diet  can  be  atoned  for,  not  by  the  taking  of  patent 
medicines,  but  by  learning  the  art  of  living,  and  of  this 
lesson,  spare  diet,  hard  work,  exercise,  and  recreation  form 
the  first  and  last  page. 

Health  of  the  body  comes  by  living  in  a  hygienic  manner. 
Health  will  come  and  will  stay  only  when  the  body  is  cared 
for  properly  and  given  sufficient  exercise  and  recreation. 

Shall  we  drink  water  at  meals.  —  Food  should  be  chewed 
until  it  is  broken  into  fine  parts  and  thoroughly  mixed  with 
the  saliva.  Thorough  mastication  is  essential.  It  not  only 
prepares  the  food  better  for  digestion  in  the  stomach  but  it 
also  prevents  overeating. 

Drink  should  not  be  used  to  wash  the  food  down  the 
esophagus.  The  food  should  be  chewed  and  mixed  with  the 
saliva  until  it  can  be  swallowed  easily.  If  one  desires  to 
drink  water  at  meals  and  follows  the  right  method  there  is 
no  harm  in  so  doing,  but  the  habit  of  using  liquid  to  wash 
the  food  down  is  easily  acquired  and  one  should  be  careful 
not  to  form  it. 

General  rules  modified  by  individual  needs.  —  The 
student  readily  sees  that  the  question  of  individual  needs 
is  important.  There  is  truth  in  the  old  adage,  "  What  is 
one  man's  meat  is  another  man's  poison."  No  cast-iron 
rules  can  be  laid  down  for  any  one's  life.  Common  sense  can 
never  be  dispensed  with.  Persons  with  moderate  powers 
of  observation  find  by  experience  what  is  best,  and  they 
should  have  will  power  enough  to  adhere  to  what  they  find 
is  best  for  them,  although  opposite  ideas  may  be  presented 


202  Healthful  Living 

to  them  as  the  only  correct  way,  by  persons  of  narrow  views. 
What  is  enough  for  one  is  a  surplus  for  another.  Sex,  age, 
occupation,  and  heredity,  each  has  its  influence  on  diet. 
The  wear  and  tear  of  an  active  body  requires  a  class  of  food 
which  to  one  of  sedentary  occupation  would  be  a  burden. 
Exercise  lights  the  fire  that  burns  up  the  refuse  of  the  body, 
and  thus  it  increases  the  appetite  and  strengthens  the  di- 
gestion. 

Indigestion.  —  If  a  person  confines  himself  closely  with 
brain  work  and  takes  no  exercise  whatever,  he  may  not 
digest  his  food  well,  but  he  need  not  think  his  digestive 
organs  unsound,  and  begin  dieting  himself.  He  should  take 
more  exercise,  and  by  better  habits  of  life  stir  up  his  circula- 
tion, use  the  food  stored  in  the  cells,  and  they  will  become 
hungry  for  more,  and  digestion  will  be  perfect.  There  is  a 
saying,  "  You  can  lead  a  horse  to  water,  but  you  can't  make 
him  drink."  So  you  may  put  food  in  the  alimentary  canal, 
but  you  cannot  make  the  cells  assimilate  it,  although,  by 
high  seasoning,  you  may  have  aroused  an  appetite  for  it. 
The  fact  that  such  food  is  not  digested  does  not  mean  that 
the  digestion  is  weak,  it  means  only  that  too  much  food  and 
too  many  condiments  have  been  used. 

Two  ways  out  of  a  difficulty.  —  Exercise  is  the  best  way 
out  of  digestive  troubles ;  yet,  if  a  student  or  office  man  is 
under  the  delusion  that  he  "  just  simply  has  not  time  "  to 
take  plenty  of  exercise,  he  may  partly  meet  the  difficulty 
and  keep  his  brain  clear  by  an  abstemious  diet. 

Cooking.  —  The  cooking  of  food  should  involve  more  than 
applying  heat  sufficient  to  burst  the  envelope  of  cellulose 
or  coagulate  the  protein.  It  should  convert  it  into  a  di- 
gestible condition.  This  is  essential,  but  it  is  also  important 
to  cook  it  in  such  a  way  that  when  served  it  will  be  pleasing 
because  the  digestion  of  the  food  is  dependent,  as  you  re- 
member, upon  psychic  stimuli.  In  this  connection,  it  should 
be  stated  that  the  frying  pan  is  an  undesirable  utensil  for  any 


The  Hygiene  of  Digestion  203 

household.  Roasting,  baking,  stewing,  boiling,  broiling,  are 
good  methods,  but  frying  should  be  abolished. 

Meat.  —  Meat  should  be  roasted  by  putting  it  into  a  hot 
.oven  at  first,  to  form  a  crust  to  keep  in  the  juices,  then  lower- 
ing the  temperature  of  the  oven  to  prevent  drying  out  and 
hardening.  When  broiling  meat,  it  should  be  turned  over 
every  ten  seconds  to  send  the  juices  back  and  prevent  their 
escape,  thus  broiling  the  meat  in  the  heat  of  its  own  juices. 
Meat  should  not  be  salted  until  after  it  has  been  cooked,  for 
salt  draws  the  juices  out. 

Cereals.  —  You  learned  that  the  starch  of  fruit,  when  it 
ripened,  was  turned  to  sugar.  Ordinary  cooking  bursts  the 
cells  of  starch  in  the  grain  and  begins  the  transformation 
into  dextrin,  a  substance  intermediate  between  starch  and 
sugar.  This  is  a  great  help,  for  the  saliva  does  not  act  upon 
raw  starch,  and  the  pancreatic  juice  acts  only  slightly  and 
after  several  hours'  delay.  Cooking  that  amounts  to  little 
more  than  moistening  and  heating  the  starch,  is  a  disad- 
vantage, and  makes  it  more  likely  to  ferment  than  if  eaten 
raw ;  but  thorough  cooking  adds  greatly  to  the  digestibility 
of  starch.  Oatmeal,  cracked  wheat,  and  other  grain  foods 
should  be  cooked  at  least  40  minutes.  Rice  should  be  washed 
in  cold  water  in  a  colander  after  cooking.  After  washing, 
the  rice  may  be  reheated  by  steaming.  It  is  then  very 
palatable. 

Bread  is  best  if  made  of  whole-wheat  flour.  It  should  be 
cooked  in  a  slow  oven,  so  that  the  inside  of  the  loaf  may  be 
well  baked.  The  loaves  should  be  made  small  and  not  touch- 
ing, so  that  there  may  be  much  crust.  Crust  (1)  cleans  the 
teeth  like  a  brush  and  makes  them  healthy  from  use ;  (2)  it 
increases  flow  of  saliva  by  its  dryness  and  the  longer 
chewing  required ;  (3)  it  is  more  easily  digested  than  the 
crumb,  or  white  portion,  as  it  resembles  sugar.  Beaten 
bread  is  the  most  digestible,  like  the  hoe  cake  and  other 
unleavened  breads.  Yeast  bread  comes  next  in  digest}* 


204  Healthful  Living 

bility.  Baking  powders  containing  alum,  and  soda,  if  not 
thoroughly  neutralized  by  sour  buttermilk,  are  injurious, 
even  to  the  healthy. 

Yeast  belongs  to  the  class  of  plants  called  fungi,  that  can 
live  in  darkness,  and  have  neither  leaves  nor  blossom.  Most 
plants  get  nourishment  from  the  soil,  air,  and  water,  but 
yeast  and  other  fungi  derive  their  sustenance  from  vegetable 
or  animal  matter  in  process  of  decomposition.  Yeast  plants 
are  microscopic  cells  of  oval  shape,  and,  like  other  plants, 
require  food  in  liquid  form.  They  cannot  absorb  dry  or 
solid  food.  Their  most  suitable  food  is  sugar.  The  flour 
of  wheat  contains  starch,  a  small  amount  of  which  is  con- 
verted into  sugar  by  the  diastase  which  lies  next  the,  bran. 
Yeast  grows  best  at  a  temperature  of  from  70°  to  80°.  A 
slow  growth  at  a  lower  temperature  favors  the  development 
of  other  micro-organisms  which  make  the  yeast  unhealthy 
and  produce  bad  flavors.  With  a  high  temperature  its 
growth  is  rapid  and  of  extremely  short  duration. 

Fermentation  *  may  go  through  several  stages  ;  in  the  first 
stage,  or  alcoholic  fermentation,  the  yeast  decomposes  the 
sugar,  splitting  it  into  alcohol  and  carbon  dioxid  gas.  This 
is  the  stage  for  bread-making,  the  gas  causing  the  bread  to 
rise.  In  the  second  stage,  or  vinegar  fermentation,  alcohol 
is  changed  to  acetic  acid  —  the  acid  in  vinegar.  Hard  wheat 
has  more  gluten  than  other  wheat,  and  the  bubbles  formed 
in  its  flour  will  not  break  easily.  Why  does  bread  from  such 
wheat  rise  well  ?  Why  is  bread  set  in  a  warm  place  to  rise  ? 
Why  does  it  "  fall  "  if  left  to  stand  too  long?  Under  what 
conditions  does  bread  made  from  yeast  become  sour  ?  Why 
does  bread  set  to  rise  in  a  cold  place  sometimes  have  a  bad 
flavor? 

Vegetables.  —  Irish  potatoes,  to  become  mealy  instead  of 
soggy,  should  be  put  into  boiling  water,  and,  after  they  are 
cooked,  the  water  should  be  poured  off,  and  the  pot  should 
be  set  on  the  back  of  the  stove  for  the  potatoes  to  dry. 


The  Hygiene  of  Digestion  205 

Roasting  them  in  the  oven  with  their  skins  on  also  retains 
their  flavor  and  makes  them  mealy. 

Onions  are  better  if  cooked,  to  drive  off  the  acrid,  irri- 
tating oil.  Raw  cabbage,  which  is  water  and  cellulose, 
is  treated  by  the  stomach  as  a  foreign  substance,  and  sent 
promptly  to  the  intestine ;  but  the  stomach  attempts  to 
digest  boiled  cabbage,  and  it  remains  there  several  hours. 
Peanuts  are  nutritious  and  digestible  if  properly  prepared. 
Boiling  water  should  be  poured  over  the  raw  peanuts  so  that 
the  skins  can  be  removed.  They  should  simmer  on  the  stove 
for  hours  until  they  can  be  easily  pressed  through  a  colander. 
This  with  the  addition  of  a  little  salt  is  a  palatable  food. 
Raw  and  roasted  peanuts  are  not  easy  to  digest. 

Eggs.  —  Eggs  should  be  cooked  by  placing  them  in  boiling 
water  and  taking  the  pot  off  the  stove.  They  cook  while 
the  water  is  cooling,  and  the  albumin  is  jellied  but  not 
hardened. 

The  fireless  cooker.  —  Cooking  meat  and  vegetables  by 
placing  them  in  a  closed  cabinet  and  providing  heat  in  the 
form  of  heated  stone  is  a  desirable  method  of  cooking.  Meats 
are  made  more  tender.  Vegetables  can  be  cooked  thoroughly 
and  yet  they  will  retain  their  form.  A  fireless  cooker  makes 
housework  easier  and  for  this  reason  alone  it  should  be  part 
of  the  furnishing  of  a  home. 

Times  for  eating.  —  Different  nations  have  various  habits 
of  eating.  The  number  of  meals  varies  from  two  to  five,  or 
even  eight,  meals  daily.  Such  facts  show  the  adaptability 
of  the  stomach  to  different  habits.  It  is  an  organ  which 
readily  forms  habits,  and  is  greatly  benefited  by  regularity. 
If  a  person  avoids  disturbing  the  stomach  between  meals 
and  allows  it  needed  rest,  both  appetite  and  digestion  are 
promoted.  Three  meals  a  day  seem  to  be  needed,  especially 
by  hard  workers.  The  Greeks  ate  two  meals  a  day,  and 
developed  the  most  beautiful  and  perfect  bodies  in  the  world, 
as  shown  by  the  statues  left  by  them. 


206  Healthful  Living 

Exercise  in  relation  to  eating.  —  Very  active  exercise  tends 
to  hinder  the  work  of  the  stomach,  but  facilitates  that  of  the 
intestines.  For  a  half  hour  after  a  full  meal,  hard  work  of 
every  kind  should  be  avoided,  but  hard  work  an  hour  or  two 
later  will  aid  digestion.  The  arrangement  of  the  meals 
must  take  into  account  the  other  habits  of  the  individual. 
For  example,  if  three  meals  are  eaten  in  twenty-four  hours, 
the  last  ought  to  be  the  lightest ;  but,  as  business  is  trans- 
acted in  large  cities,  a  business  man  can  hardly  find  time 
for  a  hearty  meal  in  the  middle  of  the  day.  Hence  he  does 
right  in  eating  a  lunch  at  noon,  and  having  the  heartiest 
meal  come  in  the  evening,  when  the  day's  labor  is  over  and 
there  is  time  to  relax.  If  he  takes  the  principal  meal  in  the 
latter  part  of  the  day,  he  should  not  eat  ,very  heartily  the 
next  morning  or  during  business  hours ;  to  do  so  would 
surfeit  the  system.  Late  suppers  should  not  be  eaten,  as 
they  prevent  sound  sleep.  The  lower  animals  may  lie  down 
in  the  shade  and  sleep  after  eating,  but  it  is  only  for  a  short 
nap.  A  nap  of  ten  minutes,  just  long  enough  to  bring  about 
relaxation,  is  often  of  benefit  after  a  meal.  During  sleep 
the  heart  beats  less  frequently  and  with  less  force;  the 
lungs  are  less  active ;  the  brain  nearly  ceases  its  activities ; 
the  muscles  relax  and  become  motionless ;  peristalsis  and 
secretion  in  the  alimentary  canal  become  slow,  and  the  di- 
gestive organs  should  have  rest.  If  a  person  is  troubled 
with  a  too  great  flow  of  blood  to  the  brain,  some  light,  di- 
gestible article  of  food  taken  just  before  retiring  may  bring 
sleep ;  but  it  should  be  taken  simply  to  regulate  the  circu- 
lation, and  should  be  so  digestible  as  to  give  little  work  to 
the  stomach.  A  farmer  will  do  a  better  afternoon's  work 
if  he  will  rest  for  half  an  hour  after  the  noon  meal. 

The  rule  that  every  individual  must  be  a  law  unto  himself 
may  be  abused  by  those  who  consult  their  appetites  alone 
without  reference  to  their  common  sense.  If  we  believe 
that  regularity  in  eating  is  desirable,  the  stomach  and 


The  Hygiene  of  Digestion  207 

appetite  can  be  trained  to  it,  although  if  one  is  used  to  eating 
at  all  times  and  between  meals,  the  desire  to  do  so  may  re- 
main for  a  time.  An  appetite  for  whisky  is  an  acquired  one, 
and  is  not  an  evidence  of  a  normal  and  healthy  demand. 
Emaciated  and  half -starved  persons  may  suffer  from  want  of 
appetite,  but  it  may  be  a  sign  that  they  should  increase  the 
activity  of  other  organs,  as  the  muscles,  not  that  they  should 
follow  the  guidance  of  appetite  and  eat  insufficient  food. 

A  good  and  healthy  appetite  comes  from  the  expenditure  of 
energy  and  rebuilding  of  the  tissues,  and  a  person  with  such 
an  appetite  enjoys  best  the  simple  foods  that  will  best  give 
energy  and  build  tissue.  The  best  pleasures  of  eating  are 
for  those  who  have  appetites  of  this  kind,  not  for  the  epicure 
or  glutton.  This  is  only  one  example  of  the  general  truth 
that  mere  pleasure  seekers  do  not  have  the  best  pleasures ; 
but  they  enjoy  life  best  whose  living  is  complete,  all  the 
duties  and  pleasures  of  life  being  given  their  proper  place. 

APPLIED   PHYSIOLOGY 

Exercise  I 

1.  How  do  you  explain  the  difference  in  the  way  a  dog  eats 
meat  and  a  horse  eats  grain?     (Compare  with  question  8.) 

2.  Clothing  and   shelter  for  man  or   beast   economize  what 
kind  of  food? 

3.  Why  does  wheat  bread  rise  better  than  corn  bread? 

4.  Why  is  corn  bread  one  of  the  most  fattening  of  grain  foods  ? 

5.  Why  is  it  that  you  can  tell  best  about  the  digestibility  of 
bread  while  you  are  slicing  it  ? 

6.  What  kind  of  persons  would  not  find  it  well  to  take  a  long 
walk  before  breakfast  ? 

7.  Why  are  late  suppers  unhealthf ul  ? 

8.  Why  should  bread  remain  longer  in  the  mouth  than  meat? 

9.  In  snowballing  what  is  the  appearance  of  the  hands  when 
they  itch  from  cold?     Why  does  ice- water  not  satisfy  the  thirst, 
but  often  produces  a  craving  to  drink  more  water? 

10.   Why  is  it  more  difficult  to  swallow  a  small  pill  than  a  large 
one? 


208  Healthful  Living 

Exercise  II 

11.  When  is  hunger  a  safe  guide? 

12.  Why  does  not  fat  meat  taste  as  well  in  summer  as  in  winter  ? 

13.  Name  organs  which  receive  more  benefit  from  the  blood 
than  they  give  to  it. 

14.  Name  organs  which  give  greater  benefits  to  the  blood  than 
they  receive  from  it. 

15.  Why  should  pork  be  thoroughly  cooked  ? 

16.  What  necessary  step  in  preparing  salt  meat  to  be  cooked 
lessens  its  nutritive  value  ? 

17.  Should  biscuits,  having  a  yellow  tint  or  dark  spots  due  to 
soda,  be  eaten? 

18.  Why,  during  an  epidemic,  are  those  who  have  used  alcohol 
as  a  beverage  usually  the  first  to  be  attacked  ? 

19.  What  is  the  effect  of  alcohol  upon  albuminous  substances? 

20.  Explain  how  it  is  that  when  people  speak  of  an  inactive 
liver  they  usually  mean  an  overworked  one. 

Exercise  III 

21.  How  does  the  possession  of  a  gall  bladder  furnish  evidence 
that  man  should  have  meal  times  and  not  eat  at  all  times  ? 

22.  Who  attains  greater  success  in  life  and  true  happiness,  the 
man  who  makes  millions  of  dollars  but  loses  his  health  by  close 
application  to  money  making,  and  has  to  live  on  gruels  and  soups, 
and  does  not  have  sound  sleep,  or  the  man  who  makes  a  living  and 
no  more,  sleeps  soundly,  enjoys  his  food,  and  has  strong  nerves? 
Which  do  you  regard  as  a  truly  successful  man?     Which  does 
public  opinion  regard  as  more  successful? 

23.  Do  you  buy  more  wood  (cellulose)  when  you  buy  beans  or 
when  you  buy  nuts? 

24.  Do  you  buy  more  water  when  you  buy  bread  or  when  you 
buy  meat  ? 

25.  Which  is  true,   the  original  saying:    "Stuff  a  cold,   and 
you  will  have  to  starve  a  fever,"  or  the  modern  way  of  stating  it? 

26.  Why  is  soda  sometimes  good  medicine  to  neutralize  a  sour 
stomach,  and  very  bad  for  digestion  if  eaten  in  bread? 

27.  What  advantage  in  digestibility  may  a  hot  biscuit  have  over 
a  loaf  of  stale  bread?     Vice  versa? 

28.  Some  physiologists  hold  that  the  eating  of  much  meat  causes 
an  irritable  temper.     Does  your  observation  of  others  or  your 
personal  experience  confirm  or  disprove  this  ? 


The  Hygiene  of  Digestion  209 

29.  Why  do  people  who  live  in  overheated  rooms  often  have 
poor  appetites? 

30.  Why  may  the  taking  of  prepared  pepsin  weaken  the  stom- 
ach? 

31.  Why  is  there  often  an  outbreak  of  colds  when  a  warm  moist 
spell  of  weather  succeeds  several  weeks  of  cold  dry  weather? 

32.  Explain  how  the  stomach  may  be  weakened  by  the  eating 
of  predigested  foods. 

APPLIED   PHYSIOLOGY 

LABORATORY  EXERCISES 

Experiment  1.    To  study  the  changes  which  take  place  in  the  diges- 
tion of  starchy  foods  in  the  mouth. 

Material.  —  Crackers,  Fehling  solutions,  test  tubes. 

Method  and  observation.  —  (a)  Test  an  unsweetened  cracker 
with  Fehling  solution  for  sugar.  Note  the  result.  (6)  Test  some 
saliva  with  Fehling  for  sugar.  Note  the  result,  (c)  Chew  some 
of  the  unsweetened  cracker  and  test  some  of  this  chewed  cracker 
with  Fehling.  Note  the  result. 

What  conclusion  would  you  draw  from  this  one  experiment  as 
regards  the  digestion  of  starch  in  the  mouth  of  the  experimenter? 
With  observation  of  other  people  what  conclusion  could  be  drawn 
as  regards  such  digestion  in  general  ? 
Experiment  2.    To  study  cooking  processes. 

1.  Try  at  home  cooking  rice  and  then  washing  it  in  a  colander 
and  compare  the  result  with  that  obtained  by  washing  the  rice 
before  cooking.     The  washing  process  removes  the  sticky  gluten 
that  has  been  set  free  by  the  cooking  process. 

2.  Notice  the  difference  in  the  white  (albumin)  of  a  fried  egg 
and  a  boiled  egg. 

GLOSSARY 

Cellulose.  —  A   substance   that  forms  the  chief  material  of   the 

structure  of  plants. 
Coagulation.  —  The   process   of   solidification   of   a   liquid.     This 

may  be  accomplished  by  means  of  heat  or  by  acids.     When 

an  egg  is  cooked  the  protein  of  the  white  coagulates. 
Congestion.  —  An  abnormal  and  excessive  accumulation  of  blood 

in  the  vessels  of  an  organ  or  a  part, 
p 


2io  Healthful  Living 

Dextrin.  —  A  brownish- white  compound  with  the  chemical  formula 
(Ci2H2oOio).  It  is  derived  from  starches  by  a  process  of  remov- 
ing two  molecules  of  water.  It  is  one  of  the  steps  in  the 
digestion  of  starches. 

Dyspeptic.  —  One  who  has  dyspepsia.  Dyspepsia  is  an  old  term  to 
denote  difficult  and  painful  digestion.  To-day  the  term  "in- 
digestion "  is  used  and  is  more  acceptable.  In  one  respect  the 
older  term  is  satisfactory.  It  comes  from  Greek  origin,  dys 
meaning  bad,  and  pepto  cook.  Bad  cooking  is  often  the  cause 
of  indigestion. 

Emulsify.  —  To  convert  into  an  emulsion. 

Emulsion.  —  A  liquid  mixture  in  which  a  fat  or  oil  is  suspended 
in  minute  globules.  Milk  is  an  emulsion.  The  butter  fat 
is  suspended  in  such  minute  globules  that  they  do  not  appear 
in  fresh  milk.  After  milk  has  "  stood  "  for  some  time,  the 
fat  will  rise  to  the  top  because  it  is  lighter  than  the  other  ele- 
ments in  the  milk. 

Fermentation.  —  A  chemical  decomposition  of  an  organic  com- 
pound usually  induced  by  living  organisms.  The  action  of 
enzymes  in  causing  chemical  change  in  digestion  is  also  spoken 
of  as  fermentation. 

Germicide.  —  A  substance  capable  of  killing  germs  (Bacteria). 
Could  be  called  bacteriocide. 

Tonic.  —  A  medicine  or  regimen  having  the  power  to  invigorate 
and  build  up  the  body.  Medicines  chiefly  by  improving  the 
appetite.  Fresh  air,  out-door  exercise,  change  of  activity, 
sleep  are  the  best  tonics  for  the  body. 


CHAPTER  XII 
THE    CIRCULATION    OF    THE    BLOOD 

I.    How  the  Circulation  of  Blood  Serves  the  Body. 
II.    The  Nature  of  Circulation. 

III.  The  Composition  of  the  Blood. 

The  work  of  the  red  corpuscles 
The  work  of  the  white  corpuscles 
The  work  of  the  plasma 

IV.  The  Heart  as  a  Pump. 

How  the  heart  works 
The  circulation  traced 
V.    The  Blood  Vessels  as  Tubes. 
Structure  of  the  vessels 
Arteries  and  veins  compared 
Adaptation  of  the  vessels 
VI.    Blood  Pressure. 

How  the  pressure  is  measured 
Modification  of  pressure  and  blood  flow 
Need  for  modification 
VII.    The  Heart  Rate. 


How  the  circulation  of  blood  serves  the  body.  —  It  will 
be  recalled  that  the  tissues  composing  the  body  are  made 
up  of  cells ;  that  these  cells  are  active  and  must  have  food ; 
that  the  food  for  the  cells  is  the  nutritive  food  elements 
(protein,  fat,  and  carbohydrate)  and  the  non-nutritive  food 
materials  (water,  and  salts) ;  that  some  of  these  substances 
undergo  slow  combustion  in  the  tissues ;  that  this  combus- 
tion or  uniting  with  oxygen  gives  rise  to  carbon  dioxide  and 
other  waste  substances.  The  blood  which  serves  as  the 
vehicle  for  the  transportation  of  food  and  the  removal  of 


212 


Healthful  Living 


waste  from  the  cells  to  the  excretory  organs,  has  other  im- 
portant functions. 

It  also  serves  in  equalizing  the  temperature  of  the  body. 
The  heat  of  the  body  is  continually  kept  at  a  certain  point 
(98.6°  F.)  in  health,  by  the  blood  vessels  bringing  to  the  sur- 
face of  the  body  the  heated  blood  and  allowing  radiation  of 
this  heat  to  occur.  The  blood  also  serves  to  protect  the 
body  from  infections  by  having  in  its  plasma,  substances 
which  protect  the  body.  The  blood  also  carries  secretions 
from  internal  glands  which  control  growth  and  development. 
The  nature  of  circulation.  —  To  have  a  circulation,  there 
must  be  a  fluid,  a  pump,  and  a  system  of  tubes  or  pas- 
sages through  which  the  fluid  is  forced.  In  a  city  water 
system,  the  fluid  is  the  water,  the  power  station  provides 
the  pump,  and  the  mains  are  the  tubes.  In  the  body  the 
fluid  is  the  blood,  the  pump  is  the  heart,  and  the  tubes  are 
the  arteries  and  veins.  In  studying  the  circulation,  there- 
fore, we  must  study  the 
blood,  the  heart,  and  the 
blood  vessels. 

Composition  of  the 
blood.  —  When  seen  un- 
der the  microscope  blood 
no  longer  appears  of  a 
uniform  red  color.  It  is 
found  to  consist  of  a 
clear,  colorless  liquid 
called  plasma,*  in  which 
floats  a  multitude  of 
small  bodies  called  cor- 
puscles .  *  The  corpuscles 

themselves  are  seen  to  be  of  two  kinds.  By  far  the  greater 
number  are  round,  yellow,  and  flattened,  but  a  few,  perhaps 
one  in  four  hundred,  are  round,  white,  and  globular,  and 
larger  than  the  yellow  ones  (Fig.  122).  The  yellow  ones 


FIG.  122.  —  Blood  cells,  a,  red  corpus- 
cles seen  from  the  side ;  b,  red  corpuscles, 
seen  on  edge,  are  run  together  in  rows 

c,  section  through  middle  of  red  corpuscle 

d,  red    corpuscle    swollen    with    water 

e,  white  corpuscles. 


The  Circulation  of  the  Blood 


213 


are  called  the  red  corpuscles,  because  the  light  shining 
through  a  great  number  of  them  gives  the  blood  a  red  color. 
The  white  ones  are  called  the  white  corpuscles.  The  follow- 
ing presents  in  tabular  form  the  elements  making  up  the 
blood : 

f  Red  blood  cells 

[Cells      \  (-lymphocytes* 

[  White  blood  cells          ( 

[  leucocytes  * 


Blood 


Water  —  90  per  cent 

f  oxygen 

Gases           I  carbon  dioxide 

[  nitrogen 

f  albumin 

tein     1  Slobulin 

I  fibrinogen 

Food 

carbohydrate  —  glucose 

chlorides 

'  sodium 

Inorganic 

carbonates      1     « 

potassium 

salts 

sulphates        f 

calcium 

phosphates    j 

magnesium 

Plasma 


Waste 

products  —  urea  and  uric  acid 

Protective 

substances  —  agglutinins,  etc. 

Growth 

determiners  —  hormones  * 

The  work  of  the  red  corpuscles.  —  The  red  corpuscles  serve 
to  carry  oxygen  (Fig.  123).  They  contain  a  substance  in 
their  protoplasm  which  has  the  power  of  combining  chemically 
with  oxygen.  This  substance  is  haemoglobin.  When  the 
red  cell  passes  in  the  pulmonary  vessels  through  the  lungs 


214 


Healthful  Living 


FIG.  123. — a,  human 
blood  corpuscles,  side 
and  front  view  ;  b,  frog's 
blood  corpuscles,  side 
and  front  view.  Both 
are  drawn  to  the  same 
scale. 


the  haemoglobin  "  takes  up  "  oxygen  in  accordance  with  the 
needs  of  the  body.  This  is  an  important  fact.  When  the 
body  has  used  oxygen  in  large  amounts, 
the  red  cells  will  be  depleted  and  so  will 
take  up  more  when  they  make  their 
next  trip  through  the  lungs. 

The  work  of  the  white  corpuscles.  — 
The  blood  of  healthy  persons  possesses 
a  certain  power  of  destroying  germs  of 
disease  which  may  enter  the  body;  this 
is  called  its  germicidal  or  germ-killing 
power.  The  germs  are  minute  one- 
celled  organisms  to  be  seen  only  through 
a  powerful  microscope.  Some  float  in 
air ;  others  are  found  in  liquids  or  solids. 
Most  kinds  of  germs  are  not  harmful  to 
man.  For  instance,  there  is  a  germ  which  gets  into  milk 
and  causes  it  to  turn  sour.  The  yeast  germ,  used  in  bread 
making,  is  a  microscopic  one-celled  plant  which  obtains  its 
nourishment  from  sugar. 

The  germicidal  power  of  the  blood  rests  in  part,  at  least, 
in  the  white  corpuscles.  When  the  flesh  is  cut,  or  when 
bacteria  lodge  in  the  tissues,  these  little  scavengers  may  be 
seen  collecting  at  the  danger  point  in  great  numbers ;  some 
of  the  germs  are  devoured  bodily  by  the  white  corpuscles ; 
others  are  killed  probably  by  substances  in  the  plasma  which 
were  formed  by  these  little  guardians.  In  no  way  is  the 
provision  for  our  welfare  better  shown  than  by  the  existence 
of  these  corpuscles  (Fig.  124). 

The  work  of  the  plasma.  —  That  the  blood  may  flow  readily 
through  every  little  tube,  it  must  be  liquid,  hence  a  large 
part  of  it  is  water.  The  water  is  important  also  as  a  solvent 
for  the  salts,  waste  products,  food,  and  other  substances 
carried.  The  gases  present  in  the  blood  are  nitrogen,  oxygen, 
and  carbon  dioxide.  The  nitrogen  is  inert  and  is  only  ab- 


The  Circulation  of  the  Blood 


sorbed  physically.  The  oxygen  is  in  chemical  combination 
with  the  haemoglobin  of  the  red  corpuscle.  The  carbon 
dioxide  which  results  from 
combustion  in  the  cells  is 
removed  by  the  blood  and 
carried  partly  in  chemical 
combination  with  various 
salts  and  partly  in  physical 
solution  in  the  plasma.  The 
food  elements  are  all  repre- 
sented. The  proteins  are 
albumin,  globulin,  and  a 
special  protein  concerned  in 
coagulation. 

If  some  blood  from  an 
animal  is  allowed  to  stand 
in  a  vessel,  it  soon  becomes 
a  red,  jelly  like  mass.  This 
change  is  called  coagulation. 
If  we  let  the  coagulated 
blood  stand,  it  gradually  ,-, 

J          FIG.   124.  —  Migration  of  white  cor- 
Separates  into  two  parts,  —     puscles  through  the  walls  of  a  vein. 

a  light  yellow  liquid  called    They  are  sh™n  **  different  stages  of 

.     *  migration.     The  red  corpuscles  remain 

Serum,  which  IS   Colored  by     in  the  stream. 

a  few    blood    cells,    and   a 

semi-solid  mass  called  the  clot,  which  contains  most  of  the 

cells  together  with  some  threadlike  fibers   (Fig.    125).     A 


FIG.  125.  —  Diagram  to  illustrate  the  process  of  coagulation.  A,  fresh 
(corpuscles  and  plasma)  ;  B,  coagulating  (formation  of  fibrin) ;  C,  coagu- 
lated (clot  and  serum) .  Plasma  minus  fibrinogen  equals  serum.  Corpuscles 
plus  fibrin  equal  clot. 


2i6  Healthful  Living 

substance  called  fibrinogen  was  in  solution  in  the  plasma. 
It  has  solidified  into  fibers,  called  fibrin  *  which,  by  entangling 
the  red  and  white  corpuscles,  caused  the  formation  of  the 
clot.  The  portion  of  the  plasma  that  remains  liquid  is  com- 
posed of  the  water  with  all  the  other  elements  in  solution. 
The  carbohydrate  element  is  represented  by  glucose.  The 
fats  vary  in  amount.  During  digestion  the  fat  content  is 
higher  than  in  the  intervals  between  digestion.  The  salts  of 
the  plasma  are  mainly  salts  of  sodium.  There  are  some  potas- 
sium salts  in  the  corpuscles,  but  the  inorganic  matter  is  repre- 
sented largely  by  the  salts  in  the  liquid  portion  of  the  blood. 

The  waste  products  which  result  from  the  breaking  down 
of  chemical  compounds  in  the  production  of  energy  are 
present  in  the  blood  on  their  way  to  the  organs  of  elimina- 
tion, the  kidneys,  skin,  and  lungs.  Urea*  and  uric  acid,*  which 
arise  mainly  from  protein  oxidation,  carbon  dioxide,  which 
comes  from  the  breaking  down  of  carbohydrate,  and  fat  are 
the  chief  substances. 

The  protective  substances  in  the  plasma  serve  to  kill 
bacteria.  It  is  known  that  many  diseases  produce  a  con- 
dition as  an  after  effect  that  protects  the  individual  ever 
afterwards  from  that  disease.  Some  of  these  substances  act 
separately  and  others  in  conjunction  with  the  white  cor- 
puscles. According  to  their  function,  they  have  been  given 
names,  such  as  bacteriolysins  (to  dissolve  bacteria) ,  agglutinins  * 
(to  produce  a  cluster),  precipitins  (to  cause  a  precipitate), 
opsonins  (to  prepare  as  food  for).  The  last  three  are  ap- 
parently concerned  more  with  making  it  possible  for  the 
white  corpuscles  to  attack  the  bacteria. 

The  growth  determiners  are  substances  produced  by 
glands  in  the  body.  The  secretions  are  taken  up  by  the 
blood  and  control,  in  some  way  not  clearly  demonstrated, 
the  growth  and  development  of  the  body.  The  glands  pro- 
ducing these  secretions  are  thyroid,  thymus,  pituitary, 
adrenal,  pancreas,  ovary,  and  testicle. 


The  Circulation  of  the  Blood 


217 


The  heart  as  a  pump.  —  The  organ  which  gives  the  push 
or  impulse  to  the  blood  and  causes  it  to  circulate  in  the  tubes 
or  vessels  is  the  heart  (Fig.  126).  The  tubes  that  conduct 
the  blood  away  from  the  heart  to  the  organs  and  tissues  are 
called  arteries.  The  tubes  through  which  it  returns  to  the 
heart  are  called  veins.  The  very  small  tubes  that  take  the 
blood  from  the  arteries  to  the  veins  where  it  begins  its  re- 
turn journey  are  called  capillaries.  The  blood  must  cir- 
culate in  order  that  it  may  go  to  the  digestive  organs  to  get 
food,  or  to  the  lungs  to  get  oxygen,  and  to  all  the  tissues  in 


Supe. 


FIG.   126.  —  Diagrammatic  section  of  heart. 

order  to  distribute  these  things,  and  to  carry  away  waste 
materials  to  the  organs  that  will  free  the  body  of  them.  Can 
you  see  in  your  mind  the  dark  color  of  a  piece  of  beef  and  the 
lighter  color  where  a  fresh  cut  is  made?  Blood  going  from 
the  lungs  to  the  tissues  is  bright  red,  about  the  color  of  a 
piece  of  new  beef  when  the  knife  cuts  into  it.  The  blood 
going  from  the  tissues  to  the  lungs  is  darker,  about  the  color 
of  the  outside  of  the  piece  of  raw  beef  some  time  after  it  is 
cut. 

The  heart  is  situated  in  the  chest,  between  the  two  lungs. 
It  is  a  hollow  muscle,  and  has  the  remarkable  power  of  con- 
tracting and  relaxing  itself  with  periodical  regularity.  The 


218 


Healthful  Living 


movement  of  contraction  is  called  the  systole  * ;  the  re- 
laxation is  called  the  diastole.*  The  period  of  systole  is 
the  systolic  phase ;  the  period  of  diastole  is  the  diastolic 
phase. 

The  hear-t  is  divided  by  a  vertical  partition  into  halves 
(Fig.  127).  The  right  half  receives  the  dark  blood  from  the 
body  and  sends  it  to  the  lungs.  The  left  half  receives  the 


Aorta 


Pu/monery 
Artery 


Superior^ 
Vena  Cava 

Pulmonary 
Veins 


Jnferior 
Vena  Cave 


Right  Ventricle 


Aorta 


FIG.   127.  —  Diagram  to  show  the  course  of  the  blood  through  the  heart. 
The  vessels  containing  impure  blood  are  drawn  darker  than  the  others. 

bright  blood  from  the  lungs  and  sends  it  to  every  part  of 
the  body.  Each  half  is  also  divided  by  a  horizontal  partition, 
but  unlike  the  vertical  ones,  these  partitions  are-  pierced 
with  openings  for  communication.  The  heart,  therefore, 
contains  four  chambers;  the  two  .upper  ones  are  called 
auricles,  the  two  lower  ones  ventricles.  The  right  auricle 
communicates  with  the  right  ventricle  just  below  it,  and  the 
left  auricle  communicates  with  the  left  ventricle. 


The  Circulation  of  the  Blood 


219 


FIG.  128.  —  The  right 
side  of  the  heart.  The 
blood  flowing  through  the 
valve  into  the 


How  the  heart  works.  —  From  all  parts  of  the  body  (ex- 

cept the  lungs)  the  blood  arrives  at  the  right  auricle,  dark 

red  in  color,  and  charged  with  carbon 

dioxide,  a  gas  that  is  unfit  for  support- 

ing life.     The  blood  has  come  through 

two   large   veins,   the   superior   vena 

cava,  from  the  head,  arms,  etc.  (Fig. 

127),  and  the  inferior  vena  cava,  from 

the  lower   parts  of  the   body.     The 

first   chamber  of  the   heart   that   it 

enters    is    the    right    auricle.      The 

auricle    contracts    and    presses    the 

blood   into  the  right  ventricle  (Fig. 

128).     It  begins  to  squeeze  together 

just  around  the  openings  of  the  veins, 

so  that  it  closes  their  openings.     The  blood,  owing  to  this, 

cannot  go  back  into  the  veins,  but  is  forced  into  the  ven- 

tricle. The  right  ventricle,  thus  filled  with  blood,  at  once 
begins  to  contract.  The  first  effect  of 
the  pressure  thus  produced  is  to  force 
blood  behind  the  flaps  of  the  tricuspid 
valve,  the  valve  between  the  auricle 
and  ventricle,  consisting  of  three  flaps 
made  of  white  fibrous  tissue.  The 
blood  behind  the  flaps  brings  the  flaps 
together  and  so  blocks  the  way  to  the 
auricle  (Fig.  129).  The  contraction 
of  the  ventricle  goes  on,  and  soon  the 
Wood  presses  hard  enough  upon  the 
semilunar  valve  to  open  it  and  go  on 

^  the  pulmonary  artery  (Fig.  129)  . 

the  semilunar  valve  opens  when  the 
pressure  in  the  ventricle  is  greater  than  the  pressure  in  the 
pulmonary  artery. 
When  the  ventricle  has  emptied  itself,  it  relaxes.    The 


FIG.  129.  —  The  blood 

eo  The 

lungs.     Tricuspid  valve 

closed,   semilunar   valves 


22O  Healthful  Living 

semilunar  valve  is  composed  of  three  pockets,  which  the 
swollen  pulmonary  artery  fills  with  blood  as  soon  as  the 
ventricle  begins  to  relax.  The  pockets  of  the  valve  are  thus 
pressed  together,  and  no  blood  flows  back  into  the  ventricle. 
The  auricle  was  relaxing  while  the  ventricle  was  contracting, 
and  it  is  already  filled  with  blood  that  has  flowed  in  from  the 
veins.  After  a  short  pause,  it  again  contracts ;  and  the 
same  action  is  repeated.  More  and  more  blood  is  thus 
driven  by  the  right  ventricle  through  the  semilunar  valve 
into  the  pulmonary  artery,  so  that  the  blood  which  is  al- 
ready in  the  artery  is  sent  on  through  the  numerous  small 
branches  and  through  the  multitude  of  fine  tubes  called 
capillaries,  which  go  through  every  part  of  the  lungs. 

In  the  lungs  the  carbon  dioxide  passes  into  the  air  passages, 
and  the  oxygen  brought  by  the  breath  goes  into  the  blood 
of  the  capillaries,  which  changes  in  color  to  bright  red.  The 
capillaries  unite  again  to  form  the  pulmonary  veins,  which 
lead  back  to  the  heart.  We  thus  see  how  the  blood  is  sent 
from  the  heart  through  the  lungs  and  back  to  the  heart. 
How  is  the  blood  sent  through  the  body  and  back  to  the 
heart  ?  We  shall  find  that  this  is  done  by  the  left  side  of  the 
heart;  that  the  two  ventricles,  acting  like  pumps,  work  in 
unison ;  that,  in  fact,  a  wave  of  muscular  contraction  start- 
ing at  the  top  of  the  heart  passes  downward  over  both  sides 
of  the  heart  at  once,  both  auricles  contracting  at  the  same  time 
and  then  relaxing  as  the  contraction  passes  to  the  ventricles. 

As  we  learned,  the  pressure  from  the  right  ventricle  keeps 
the  blood  moving  through  the  pulmonary  artery,  the  capil- 
laries of  the  lungs,  and  the  pulmonary  vein.  It  returns  to  the 
heart  again,  and  this  time  it  enters  the  left  auricle.  When 
the  left  auricle  is  full,  it  contracts  and  drives  the  blood 
through  a  valve  called  the  mitral  valve,  into  the  left  ven- 
tricle (Fig.  130).  The  left  ventricle  (at  the  same  time  with 
its  mate,  the  right  ventricle)  then  contracts,  forcing  the 
blood  behind  the  flaps  of  the  mitral  valve,  closing  the  way 


The  Circulation  of  the  Blood 


221 


back  to  the  left  auricle.  The  pressure  of  the  ventricle  opens 
the  semilunar  valve  in  the  mouth  of  the  great  aorta,  which 
is  the  large  artery  carrying  the  blood  from  the  left  ven- 
tricle. The  aorta  takes  the  blood  to  every  part  of  the  body 


FIG.  130.  —  View  of  the  orifices  and  valves  of  the  heart  from  below,  the 
whole  of  the  two  ventricles  being  cut  away,  a,  aorta  ;  b,  pulmonary  artery, 
each  with  its  three  cups  of  the  closed  semilunar  valves  seen  convex  from 
below ;  opening  between  right  auricle  and  right  ventricle,  surrounded  by 
three  flaps  of  the  tricuspid  valve  with  chordae  tendineae  between  them,  to 
which  three  cords  are  tied,  taking  the  place  of  the  papillary  muscles,  d, 
opening  between  left  auricle  and  left  ventricle,  with  two  flaps,  of  the  mitral 
valves  and  chordae  tendinae,  to  which  cords  are  tied. 

This  figure  may  be  said  to  show  the  roof  of  the  two  ventricles,  with  the 
two  great  valves,  by  which  the  blood  enters  the  ventricles  and  the  two  great 
valves  by  which  it  leaves  them.  All  the  openings  of  the  ventricles  are  up- 
ward. 

except  the  lungs.  It  gives  off  smaller  arteries,  and  the 
division  is  repeated  until  arteries  are  supplied  to  every 
organ  and  tissue.  In  the  tissues  the  arteries  empty  into 
smaller  tubes  called  capillaries.  The  aorta,  with  its  branches, 
becomes  distended  with  blood,  and  as  more  and  more  is 
forced  into  it  by  the  left  ventricle  at  each  heart  beat,  the 


222 


Healthful  Living 


distention  is  kept  up,  and  some  of  the  blood  already  in  the 
aorta  is  forced  along  its  branches,  and  the  same  pressure 

forces  it  through  the  capillaries 
and  into  the  veins  (Plates  V 
and  VIII). 

The  blood  flows  slowly 
through  the  capillaries  and 
performs  its  function  of  ex- 
changing substances  needed 
for  those  used  up.  It  next 
goes  into  the  veins  on  the 
return  journey  to  the  heart, 
where  it  enters  the  right 
auricle  again,  which  was  our 
starting  place  in  this  descrip- 
tion (Fig.  131). 

The  circulation  traced. — The 
blood  comes  from  the  tissues 
through  the  veins  and  enters 
the  right  auricle,  goes  through 
the  tricuspid  valve  into  the 
FIG.  131.  — Diagram  illustrating  ventricle,  then  through  the 

the   circulation,     a,  right  auricle ;  „  .         . ,  , , 

semilunar  valve  it  enters  the 


b,  left  auricle  ;  c,  right  ventricle ; 
d,  left  ventricle ;  e,  vena  cava 
superior ;  /,  vena  cava  inferior ; 
g,  pulmonary  arteries ;  h,  lungs ; 
i,  pulmonary  veins  ;  j,  aorta ;  k,  ali- 
mentary canal ;  I,  liver ;  ra,  hepatic 
artery  ;  n,  portal  vein ;  o,  hepatic 
vein ;  follow  the  arrows  and  see 
whether  you  come  around  to  the 
starting  point  again. 

the    aorta    by   the    semilunar 

valve,  thence  to  the  capillaries  of  the  system,  thence  to  the 
veins,  and  through  them  it  returns  to  the  heart,  completing 
the  circulation. 

Blood  vessels  as  tubes.  —  The  blood  tubes  are  built  of 
tissues  so  arranged  that  they  provide  the  correct  kind  of 


pulmonary  artery.  Travers- 
ing the  capillaries  of  the  lungs, 
it  goes  by  the  pulmonary 
veins,  to  the  left  auricle,  then 
through  the  mitral  valve  to 
the  left  ventricle,  thence  into 


The  Circulation  of  the  Blood 


223 


tube  needed  for  the  circulation  of  blood  in  the  body.  They 
differ  in  their  properties  from  galvanized  pipe  that  is  used 
in  water  supply  systems,  and  these  differences  are  important. 


FIG.  132.  —  Transverse  section  of  part  of  the  wall  of  an  artery,  highly 
magnified,  a,  epithelial  (endothelial)  layer,  or  inner  coat ;  b,  muscular  layer, 
or  middle  coat ;  c,  outer  coat,  consisting  of  connective  tissue. 

In  order  to  understand  how  the  arteries,  veins,  and  capil- 
laries are  adapted  to  their  work,  we  will  study  their  anatomy. 
We   shall   find   three   kinds   of 
tissue  (Fig.  132)  used  in  their 
construction,  —  epithelial  tissue 
to  prevent  friction,*  connective 
tissue  to  give  both  strength  and 
elasticity,  *  and  muscular  tissue 
to  enable  the  vessels  to  change 
in  size. 

Structure  of  the  vessels.  —  The 
epithelial  tissue  forms  the  inner- 
most layer  of  the  vessels.  The 
endocardium  or  inner  lining  of 
the  heart  is  formed  of  this  mem- 
branous layer,  and  is  continued 
throughout  the  arteries,  capil-  FlG  133.  _  Epithelial  cells 

laries,     and      veins.        In     these     forming  the  walls  of  capillaries, 
vessels    the  inner  mat  is  oallpH     The  nuclei   and  the  outlines  of 

VtyOOV/lO*        l/llt/       llllltyl       L-V/dU       Ife        CdliL'd  ,1  11  i  ml  f 

the  cells  may  be  seen.     The  form- 
the   endothelmm.      The    epithe-     ing  of  the  thin  tubular  walls  of 

Hal    Cells    forming    this    Smooth     ^e  capillaries  is  one  of  the  most 

curious  among  the  many  wonder- 
layer    are     thin     and     flat,    and     ful  feats  accomplished  by  the  cells. 


224 


Healthful  Living 


serve  to  diminish  friction.  The  walls  of  the  capillaries,  the 
smallest  vessels,  consist  simply  of  this  epithelial  membrane 
(Fig.  133). 

The  middle  coat  is  muscular  and  is  made  up  of  the  muscle 
cells  arranged  in  circular  fashion.  The  muscle  is  more  abun- 
dant in  the  arteries  than  in  the  veins,  but  is  present  in  both. 
The  outer  coat  is  made  of  connective  tissue.  This  'layer 
is  outside  of  the  muscular  tissue,  and  forms  the  outer  surface 
of  the  artery.  It  contains  both  white  fibers  and  yellow 

elastic  fibers 
(Fig.  132).  In 
fact,  some  of  the 
yellow  elastic 
fibers  (Fig.  132) 
are  found  also  in 
the  other  coats. 
The  muscular 
and  connective 

FIG.   134.  —  An  artery  and  corresponding  vein  cut  .               , 

across.     A,  artery;    B,   vein;    a,    endothelial  cells;  tlSSUe   layers    be- 

b,  muscular  coat ;    c,  connective  tissue.     Notice   the  come  still  thicker 

nuclei  of  endothelial  cells,  and  the  greater  amount  of  .               . 

muscular  tissue  in  the  artery.  m  the  larger  ar- 

teries.     So    the 

wall  of  an  artery  consists  of  three  layers :  (1)  the  endo- 
thelium;  (2)  the  muscular  coat;  (3)  the  connective  tissue 
coat  on  the  outside  (Figs.  132  and  134).  The  arteries  are, 
therefore,  very  firm  and  elastic,  and  do  not  collapse  when 
they  are  cut,  but  stand  open,  and  the  flow  of  blood  through 
them  is  unobstructed.  The  walls  of  the  veins  consist  of  the 
same  three  layers.  Their  walls  are  not  so  thick  as  those 
of  the  arteries,  for  the  muscular  and  connective  tissue  layers 
are  much  thinner  (Fig.  134).  When  a  vein  is  cut  it  col- 
lapses, that  is,  the  thin  walls  fall  together,  and  the  bleeding 
is  stopped  unless  the  vein  is  large. 

Arteries  and  veins  compared.  —  (If  this  is  made  a  written 
exercise,  underline  the  words  which  you  supply.) 


The  Circulation  of  the  Blood  225 

Walls.  —  The  walls  of  the are  very  elastic,  while  the 

walls  of  the are  slightly  elastic.  The  walls  of  the 

are  thicker  and  stiffer  than  the  walls  of  the  .  It  is 

necessary  that  they  should  be  so,  because  they  must  sustain 
the of  the . 

Work  of  Each.  —  The  arteries  take  pure  blood  from  the 
to  the ,  and  impure  blood  from  the to  the 


The  veins  take  pure  blood  from  the to  the ,  and  im- 
pure blood  from  the to  the . 

Connections  at  Heart.  —  The  —  —  are  connected  with  the 
auricles.  The  —  —  are  connected  with  the  ventricles. 

Rate  of  Flow.  —  The  blood  flows  more  rapidly  in  the 


Manner  of  Flow.  —  The  blood  in  the flows  uniformly. 

The  blood  in  the flows . 

Control  of  flow.  —  The are  abundantly  supplied  with 

•.  The  — —  have  none. 


Location.  —  The  arteries  as  a  general  rule  are  located . 

The  veins  are  generally  located .     This  adds  to  the 

of  the  body. 

Definitions.  —  The  arteries  are  tubes  that  carry  blood 
(both  pure  and  impure)  -  -  the . 

The  veins  are  tubes  that  carry  blood  (both  pure  and  im- 
pure)   the  — — . 

Accidents.  —  If  an  artery  is  cut,  the  pressure  is  to  be  ap- 
plied   the  cut  and  the .  If  a  vein  is  cut,  the  pres- 
sure is  to  be  applied the  cut.  A  cut  vein  may  be  told 

from  a  cut  artery  in  the  three  following  ways  :  — 

Adaptation  of  the  vessels.  —  The  white  fibers  of  the  con- 
nective tissue  coat  (Fig.  132)  give  strength  and  firmness  to 
the  vessel,  and  the  yellow  elastic  fibers  give  elasticity.  The 
muscular,  or  middle  coat  enables  the  arteries  and  veins  to 
change  in  size,  and  the  inner,  or  endothelial  layer  gives 
smoothness  and  prevents  friction.  Why  are  these  three 
properties  necessary  to  blood  vessels  ? 
Q 


226  Healthful  Living 

Elasticity  of  the  Blood  Vessels.  —  The  aorta  and  its 
branches  are  full  of  blood  all  the  time.  When  the  left 
ventricle  with  its  great  muscular  walls  contracts,  the  blood 
cannot  move  forward  into  the  narrow  arteries  and  capil- 
laries fast  enough  to  make  room  for  the  new  supply  so  sud- 
denly sent  out  of  the  ventricle.  Therefore,  the  aorta  be- 
comes more  than  full.  If  a  cup  is  full,  it  cannot  become 
"  fuller  "  ;  not  so  with  an  artery.  The  yellow  elastic  fibers 
of  its  connective  tissue  allow  it  to  expand  as  a  thin  rubber 
hose  does  under  pressure.  The  first  part  of  the  aorta  having 
expanded  to  receive  the  incoming  blood,  the  portion  of  the 
aorta  just  ahead  of  the  expanded  portion  is  less  tense,  or 
tight,  so  the  stretched  elastic  fibers  contract  and  force  blood 
into  it,  expanding  it  in  turn.  Thus  a  wave  of  expansion 
travels  along  the  blood  vessel.  It  is, called  the  pulse  and 
may  be  most  easily  felt  in  the  wrists  and  neck.  The  dis- 
tended elastic  walls  exert  pressure  on  the  blood  in  the  arteries, 
and  this  presses  some  of  the  extra  blood  out  of  them  into  the 
capillaries.  As  much  blood  as  is  being  pressed  on  into  the 
capillaries  is  being  thrown  into  the  aorta  by  the  beat  of  the 
heart ;  so  that  during  life  a  distention  is  always  kept  up, 
and  the  blood  in  the  vessels  is  always  under  pressure.  Al- 
though the  arteries  may  get  rid  of  the  additional  distention 
following  each  heart  beat,  there  is  a  normal  distention  that 
always  remains.  It  has  existed  ever  since  life  began,  and 
will  remain  until  the  heart  ceases  to  beat.  The  pulse,  there- 
fore, is  only  an  additional  distention  following  the  contrac- 
tion of  the  ventricle. 

You  should  not  think  that  the  muscular  layer  actively 
contracts  and  helps  to  send  along  the  pulse ;  for  the  pulse  is 
simply  the  passive  stretching  and  contracting  of  the  elastic 
tissue ;  as  a  wave  travels  across  a  pond  when  a  stone  is 
dropped  into  the  water.  The  force  of  the  pulse  is  furnished 
by  the  heart.  What,  then,  is  the  purpose  of  the  muscular 
layer  in  the  arterial  wall  ?  . 


The  Circulation  of  the  Blood  227 

Use  of  the  Muscular  Coat.  —  The  body  of  an  adult  con- 
tains about  five  quarts  of  blood.  We  have  learned  that  the 
blood  supplies  the  substances  needed  for  the  activity  of 
each  organ.  If  an  organ  is  working,  it  needs  more  blood 
than  usual,  and  it  is  supplied  by  the  other  organs  that  are 
at  rest ;  they  get  along  with  less  blood  for  the  time.  The 
muscular  coat  of  the  blood  vessels  makes  this  possible.  This 
coat  is  usually  in  a  condition  of  slight  contraction,  but  the 
nerves  controlling  the  muscular  coat  in  the  blood  tubes  of 
the  active  organs  may  cease  to  act,  thus  allowing  the  muscu- 
lar coat  to  relax  and  the  blood  tubes  to  enlarge  under  the 
pressure  from  the  heart,  so  that  the  active  organs  may  ob- 
tain the  additional  supply  of  blood  needed.  While  this  is 
happening,  part  of  the  pressure  in  the  blood  tubes  of  the 
inactive  organs  is  relieved  and  they  become  smaller.  If 
cold  air  strikes  the  face,  the  nerves  stimulate  the  muscular 
coat  of  the  blood  tubes  in  the  face  to  contract  more  strongly 
than  usual,  and  the  face  turns  white.  This  driving  of  the 
warm  blood  from  the  face  saves  heat  to  the  body,  which 
would  be  lost  if  the  warm  blood  remained  in  the  skin.  Thus 
the  amount  of  blood  circulating  in  any  organ  is  regulated 
by  means  of  the  muscular  coat  of  the  blood  vessels  and  of 
the  action  of  the  nerves  upon  this  coat. 

Use  of  the  Inner  Coat.  —  We  learned  that  the  inner  coat 
of  the  heart  and  blood  vessels  is  made  of  epithelial  tissue, 
like  that  which  forms  the  outer  layer  of  the  skin,  and  the 
smooth  lining  of  the  mouth  and  other  organs.  This  lining 
membrane  is  very  smooth  and  thus  friction  is  lessened.  The 
friction,  however,  is  inconsiderable  in  the  large  vessels ;  but 
in  the  smaller  vessels  it  is  greater ;  and  in  the  minute  capil- 
laries it  becomes  of  very  great  importance.  We  see,  there- 
fore, why  it  is  necessary  to  have  this  smooth  coat  in  the 
capillaries,  although  the  muscular  and  connective  coats  are 
not  prolonged  into  them.  It  should  be  stated  here  that 
although  the  extremely  minute  size  of  the  capillary  tubes 


228  Healthful  Living 

increases  the  friction  and  the  pressure  which  the  heart  must 
expend  in  sending  the  blood  through  them,  yet  their  re- 
sistance to  the  blood  flow  is  lessened  by  their  great  capacity. 
The  united  capacity  of  the  capillaries  is  six  hundred  times 
that  of  the  blood  arteries  that  supply  them.  In  the  capil- 
laries the  blood  flows  slowly  like  a  river  which  flows  into  and 
out  of  a  lake. 

Blood  pressure.*  —  The  force  with  which  the  heart  sends 
the  blood  into  the  vessels  and  the  resistance  offered  to  the 
flow  produces  a  pressure  in  the  arteries.  This  pressure  is 
greatest  in  the  aorta  and  gradually  decreases  in  the  course 
of  the  vessels  until  in  the  veins  that  come  into  the  heart  it 
has  fallen  nearly  to  zero.  This  pressure  in  the  arteries  is 
fluctuating.  At  each  beat  of  the  heart  it  is  increased  by  the 
push  given  by  the  volume  of  blood  forced  out  of  the  left 
ventricle,  but  as  this  wave  of  pressure  passes  toward  the 
capillaries  it  grows  less  just  as  the  ripples  on  a  lake  will  de- 
crease in  size  from  the  point  where  a  stone  was  thrown  into 
the  water.  This  wave  of  pressure  gradually  decreases,  until 
in  the  capillaries  the  flow  of  blood  is  now  constant,  and 
owing  to  the  resistance  the  pressure  has  become  less.  After 
passing  through  the  capillaries,  the  pressure  in  the  veins 
continues  to  fall  until  it  reaches  the  heart  again. 

We  shall  learn  later  how  the  contractions  of  the  muscles 
and  their  squeezing  effect  upon  the  veins  passing  through 
or  beneath  them,  aid  the  heart  to  move  the  blood;  also 
how  the  expansion  and  contraction  of  the  lungs  act  as  a 
great  pump ;  and  how  these  aids,  together  with  changes  of 
posture,  enable  the  blood  to  reach  the  heart  again.  If  one 
stands  perfectly  still  for  some  time,  the  blood,  owing  to  its 
weight  and  the  lack  of  pressure  on  the  veins,  slowly  con- 
gests in  the  veins  in  the  lower  part  of  the  body,  and  the 
consequences  may  be  serious. 

Hence  the  pressure  is  greatest  in  the  arteries,  less  in  the 
capillaries,  and  least  of  all  in  the  veins. 


The  Circulation  of  the  Blood 


229 


How  the  pressure  is  measured.  —  This  blood  pressure,  as 
it  is  called,  can  be  measured  (Fig.  135)  and  it  is  found  that 
for  normal  adults  it  is 
nearly  constant.  The 
systolic  pressure  is  that 
pressure  which  exists  dur- 
ing the  contraction  of  the 
heart  and  is  stated  to  be 
from  110  to  120  m.m.  of 
mercury  1 ;  the  diastolic 
pressure  is  that  pressure 
existing  during  the  re- 
laxation of  the  heart  and 
is  found  to  be  about 
65  m.m.  of  mercury.  It 
has  been  found  also  that 
whatever  increases  the 
force  of  the  heart's  beat 
will  increase  the  blood 


pressure  and  vice  versa; 
and  whatever  increases 
the  resistance  to  the  flow 
in  the  capillaries  will  in- 
crease the  blood  pressure 
and  vice  versa. 

The  blood  pressure  is  an  indication  of  health  in  the  body 
and  hence  it  is  measured  to  determine  certain  conditions. 
The  instrument  used  for  measuring  the  pressure  is  called 
a  sphygmomanometer  (Fig.  135) . 


FIG.  135.  —  Blood  pressure  machine 
(sphygmomanometer) .  This  instrument 
determines  the  force  which  exists  within 
the  arteries  under  different  conditions. 


1  Blood  pressure  is  usually  measured  in  terms  of  millimeters  of  mercury. 
This  means  that  the  force  exerted  in  the  blood  vessel  would  support  a  unit 
column  of  mercury  of  a  certain  height.  The  height  in  this  case  would  be 
110  to  120  m.m.  The  examination  of  college  freshmen  by  Dr.  Lee  at  Har- 
vard, and  my  own  examinations  at  the  University  of  Cincinnati,  indicate 
that  the  normal  is  higher  than  the  120  m.m.  usually  given.  It  may  be  con- 
sidered normal  at  130  m.m.  mercury. 


230  Healthful  Living 

Modification  of  pressure  and  blood  flow.  —  We  learned  that 
the  ability  to  do  this  lies  in  the  muscular  or  middle  coat  of 
the  vessels,  and  that  the  muscular  coat  in  turn  is  controlled 
by  the  nerves.  The  nerves  that  control  the  sizes  of  the 
blood  vessels  are  called  vasomotor  nerves  and  are  of  two 
kinds.  One  kind,  the  constrictor  nerves,  stimulates  the 
walls  of  the  blood  vessels  to  contract,  while  the  other  kind 
of  vasomotor  nerves,  called  the  dilator  nerves,  neutralizes 
or  inhibits  the  effect  of  the  constrictors,  and  thus  allows  the 
blood  tubes  to  enlarge.  The  regulation  is  involuntary,  or 
beyond  the  control  of  the  will;  for  instance,  the  blood 
vessels  of  the  brain  may  become  enlarged  and  the  great 
pressure  there  cause  a  headache,  but  the  will  cannot  drive 
it  away.  We  sit  before  a  fire,  and  the  face  becomes  red  as 
the  warmth  soothes  the  constrictor  nerves  into  inactivity; 
or  the  constrictors  leading  to  the  face  may  become  paralyzed 
by  mental  confusion  and  we  blush. 

The  amount  of  blood  passing  through  one  organ  may  be 
increased  by  the  vasomotor  nerves,  but  it  is  only  because 
the  amount  going  through  the  enlarged  vessels  of  that  organ 
•has  been  withdrawn  from  other  organs  whose  blood  tubes, 
not  being  enlarged  just  then,  afford  greater  resistance  to  the 
passage  of  the  blood  than  the  dilated  vessels  afford.  But 
can  the  total  amount  of  blood  reaching,  in  a  given  time, 
not  a  single  organ  only,  but  all  the  organs  in  the  body,  be 
increased  ?  Yes,  for  if  the  one  and  one  fourth  gallon  of  blood 
flow  faster  all  over  the  body,  more  fresh  blood  will  reach 
each  organ.  This  is  accomplished  by  faster  or  stronger 
beating  of  the  heart. 

During  rapid  general  exercise,  as  running,  when  the  de- 
mands of  the  body  are  increased,  the  heart  beats  faster,  as 
you  have  doubtless  observed.  When  the  body  in  general 
is  at  rest,  as  during  sleep,  the  heart  beats  more  slowly.  Thus 
the  general  blood  supply  is  regulated. 

But  how  is  the  heart  itself  regulated?     For  these  facts 


The  Circulation  of  the  Blood  231 

show  two  things :  first,  that  we  cannot  directly  control  it 
by  the  will ;  and  second,  that  there  is  something  in  the  body 
that  does  control  the  heart,  and  perhaps  our  wills  may  in- 
fluence the  beating  of  the  heart  indirectly.  The  heart,  like 
the  blood  vessels  and  the  muscles  in  general,  is  supplied 
with  nerves ;  but  there  is  this  difference,  namely,  that  the 
heart  can  go  on  beating  without  receiving  impulses  along  its 
nerves.  The  heart  of  a  frog,  after  being  cut  out  of  the  body, 
will  go  on  beating  for  several  hours  if  it  is  kept  moist ;  if  it  is 
cut  into  several  pieces,  the  pieces  will  go  on  beating.  It  is 
the  property  of  the  heart  muscle  to  contract,  and  it  will  do 
so  as  long  as  its  protoplasm  is  alive. 

Need  for  modification. — We  have  learned  that  there  is  a 
mechanism  by  which  the  amount  of  blood  in  any  part 
may  be  modified.  It  is  indeed  necessary  that  this  be 
so.  The  necessity  for  this  comes  from  the  fact  that 
if  the  one  and  one  fourth  gallon  of  blood  were  evenly 
distributed,  none  of  the  organs  would  be  capable  of 
any  powerful  and  effective  action.  A  person  weighing 
157  pounds  has  only  12  pounds  of  blood,  for  the  blood  is 
Y1^  of  the  total  weight  of  the  body.  There  is  not  enough 
blood  in  the  body  to  distend  all  of  the  blood  vessels  at  once. 
The  skin  alone  with  all  of  its  blood  vessels  distended  could 
contain  two  thirds  of  all  the  blood  in  the  body.  The  veins 
have  twice  the  capacity  of  the  arteries ;  they  could  contain 
every  drop  of  blood  in  the  body. 

When  the  brain  works,  it  requires  more  blood.  When 
digestion  is  in  progress,  the  lining  of  the  digestive  organs 
blushes  a  rosy  red  and  the  digestive  fluids  are  poured  out. 
During  the  digestion  of  a  hearty  meal,  one  will  not  do  his 
best  thinking.  When  a  muscle  is  used,  the  dilator  nerves 
act,  the  blood  tubes  in  the  muscle  become  enlarged,  and  its 
supply  of  blood  increases  to  serve  it  during  its  action. 

The  impulses  that  run  along  the  vasomotor  nerves  arise  in 
the  enlargement  at  the  top  of  the  spinal  cord  called  the  me- 


232  Healthful  Living 

dulla  oblongata .  The  part  of  the  medulla  that  in  this  way  regu- 
lates the  caliber  of  the  arteries  is  called  the  vasomotor  center. 
It  is  constantly  sending  impulses  along  the  constrictor  fibers 
so  as  to  keep  the  muscles  of  the  arteries  slightly  contracted. 
The  vasomotor  center  thus  keeps  a  rein  upon  the  arteries, 
holding  them  in  a  condition  of  tone,  as  this  slight  contraction 
is  called.  Sudden  paleness,  due  to  fear,  is  brought  about 
by  extra  strong  impulses  from  the  vasomotor  center,  caus- 
ing the  muscular  walls  of  the  small  arteries  of  the  face  to 
grip  the  vessels  tight  and  driving  the  blood  from  the  face. 
Alcohol  destroys  the  tone  of  the  blood  tubes.  From  tem- 
porary drinking  the  face  becomes  red ;  from  habitual  drink- 
ing swollen  blood  .tubes  in  the  nose  become  purple  and  the 
"  rum  blossom  "  results. 

The  heart  rate.  —  The  rate  of  contraction  of  the  heart  is 
controlled  by  nerves.  The  nerves  act  not  to  make  the  muscle 
contract  but  to  regulate  the  frequency  of  the  beats. 

A  nerve  called  the  vagus  nerve,  extending  from  the  medulla 
oblongata  to  several  organs,  goes  to  the  heart ;  and  gentle 
impulses  which  are  almost  always  passing  down  the  vagus 
nerve  from  the  medulla  oblongata,  restrain  the  heart  from 
too  great  activity,  and  are  the  chief  means  of  regulating  the 
strength  and  frequency  of  its  beats.  When  an  animal  re- 
quires a  greater  supply  of  blood,  as  in  running,  these  im- 
pulses for  a  time  cease,  and  the  heart  beat  is  quicker  and 
stronger. 

There  are  other  nerves,  part  of  the  autonomic  nervous 
system,  called  accelerator  nerves,  connected  with  the  spinal 
cord  below  the  point  at  which  the  vagus  branches,  that 
bring  impulses  to  the  heart  which  are  opposite  in  effect  to 
those  brought  by  the  vagus.  These  impulses  also  start 
in  the  medulla ;  they  cause  a  quickening  and  strengthening 
of  the  beats  (Fig.  174).  Do  the  vagus  nerve  fibers  or  the  ac- 
celerator nerve  fibers  resemble  the  whip  which  a  driver  uses 
in  driving  a  horse?  Which  kind  corresponds  to  the  reins? 


The  Circulation  of  the  Blood  233 

Thus  the  need  of  the  body  for  a  greater  or  less  active  blood 
supply  is  regulated  by  controlling  the  rate  and  strength  of 
the  heart  beats.  If  the  nerves  are  all  in  order,  the  heart 
beats  more  slowly  when  the  tissues  of  the  body  need  little 
blood,  and  more  rapidly  when  the  tissues  need  more  food  or 
more  oxygen.  But  quickening  of  the  heart  beats  cannot 
send  more  blood  through  one  organ  without  sending  more 
blood  through  all  the  organs,  hence  it  is  not  so  delicate  a 
means  of  regulating  the  blood  supply  as  the  vasomotor 


By  the  nerve  mechanism  explained  in  the  preceding  para- 
graphs, it  is  learned  that  the  rate  of  the  heart  can  be  ad- 
justed. The  heart  rate  is  not  the  same  for  all  people.  It 
varies  according  to  sex,  size,  and  age.  The  average  rate  in 
women  is  80  beats  a  minute,  in  men  70  beats  per  minute. 
Tall  individuals  have  a  slower  pulse  than  short  ones  of  the 
same  age  and  sex.  This  is  true  also  for  animals  other  than 
man  as  shown  in  the  following  : 

Elephant      .......  25-28  beats  per  minute 

Horse       .     .......  36-50  beats  per  minute 

Rabbit     .....     ...  140-150  beats  per  minute 

Mouse     ........  660-670  beats  per  minute 

The  rate  is  highest  in  infancy  and  decreases  in  adult  life. 
In  extreme  old  age  it  goes  up  again.  The  following  indicates 
the  heart  rate  for  different  ages  : 

At  birth     ........  140  beats  per  minute 

Infancy     ...     .....  120  beats  per  minute 

Childhood      .     .     .     .     .     .     .  100  beats  per  minute 

Youth  .........  85  beats  per  minute 

Adult    .........  72  beats  per  minute 

Old  age      ........  70  beats  per  minute 

Extreme  age       ......  75-80  beats  per  minute 

GLOSSARY 

Agglutinin.  —  A  chemical  product  in  the  blood  which  arises  as  a 
defense  to  protect  the  body  from  disease-producing  bacteria. 


234  Healthful  Living 

The  agglutinin  has  the  power  of  massing  the  bacteria  so  that 
they  may  be  readily  ingested  by  the  leucocytes. 

Blood  pressure.  —  The  pressure  which  the  blood  exerts  in  the  blood 
vessels.  It  is  measured  by  an  instrument  called  the  sphygmo- 
manometer. 

Corpuscle.  —  One  of  the  cells  of  the  blood.  We  speak  of  the  red 
corpuscle  and  of  the  white  corpuscle. 

Diastole.  —  The  period  in  which  the  heart  is  not  contracting.  It 
includes  the  time  of  relaxation  of  the  heart  muscles  and  the 
rest  before  the  next  contraction. 

Elasticity.  —  The  property  of  tissue  by  virtue  of  which  the  part 
tends  to  return  to  its  former  size  or  position. 

Fibrin.  —  A  substance  formed  when  the  blood  clots.  In  the  blood 
is  a  protein  called  fibrinogen.  When  blood  is  drawn  from  a 
blood  vessel,  the  fibrinogen  changes  into  fibrin.  The  fibrin 
is  a  tough,  elastic  structure  and  it  holds  the  blood  cells  in  a 
firm  mass.  This  is  the  clot. 

Friction.  —  Resistance  to  motion  due  to  bodies  rubbing  in  contact 
with  other  bodies. 

Hormone.  —  A  secretion  from  glands  in  which  the  product  of  the 
gland  is  not  passed  out  through  a  duct,  but  passes  directly 
into  the  blood.  Sterling  invented  the  name ;  the  Greek 
word  opvdw,  meaning  to  stir  up,  to  excite,  was  used  because 
of  the  excitatory  properties  of  the  secretion. 

Leucocyte.  —  One  of  the  white  corpuscles.  It  is  capable  of  amoe- 
boid movement  and  ingests  bacteria.  A  leucocyte  has  a 
three-lobed  nucleus. 

Lymphocyte.  —  One  of  the  white  corpuscles.  Lymphocytes  are 
of  the  large  and  small  variety.  They  have  a  single,  spherical 
nucleus. 

Plasma.  —  The  liquid  portion  of  the  blood. 

Systole.  —  The  contraction  of  the  heart. 

Urea.  —  A  soluble,  colorless,  crystalline  compound,  (CO(NH2)2). 
It  is  formed  in  the  oxidation  of  protein  in  the  body  and  is 
excreted  by  the  kidneys. 

Uric  Acid.  —  A  white  chemical  compound  composed  of  carbon, 
hydrogen,  nitrogen,  and  oxygen  (CeH^N^s).  It  results  from 
incomplete  combustion  in  the  body.  At  one  time  it  was 
thought  to  be  the  cause  of  rheumatism,  but  it  is  known  now 
that  rheumatism  is  caused  by  other  conditions. 


CHAPTER  XIII 
THE   CIRCULATION   OF  THE  BLOOD  (Continued) 

I.     How  the  Heart  Is  Aided  in  Its  Work. 
By  valves  in  the  veins 
By  exercise 
By  the  lungs 
By  massage  and  position 
II.     The  Lymphatic  Circulation. 

How  the  nourishment  gets  from  the  blood  into  the  tissues 
Lymph 

The  origin  and  course  of  the  lymphatics 
What  makes  the  lymph  flow 
The  lymphatic  glands 
The  spleen 
III.    Hygiene  of  the  Circulation. 

The  importance  of  good  circulation 

Taking  cold 

Effects  of  unusual  exercise 

Sleep  and  the  blood 

The  influence  of  thought  and  feeling 

Clothing 

Injury  to  the  blood  vessels 

The  effect  of  alcohol 

The  "  tobacco  heart  " 

Purification  of  the  blood 


How  the  heart  is  aided  in  its  work.  —  The  heart  seems  to 
be  constantly  at  work,  but  such  is  not  the  case.  As  a 
matter  of  fact,  the  heart  occupies  nearly  as  much  time  in 
resting  as  in  working.  It  works  for  about  half  a  second  and 
rests  for  about  half  a  second.  Yet  it  does  work  in  a  day  equiv- 
alent to  raising  a  ton  of  coal  nearly  two  hundred  feet.  This 

235 


236 


Healthful  Living 


Pec fora/73 
Major 


work  of  the  heart  is  aided  by  the  valves  in  the  veins,  by  mus- 
cular exercise,  by  the  lungs,  and  by  massage  and  position. 

By  valves  in  the  veins.  —  In- 
crease the  circulation  in  the  arm 
by  exercising  it  for  a  few  minutes. 
The  veins  in  the  front  of  the  wrist 
will  then  be  plainly  visible  (Fig. 
136).  The  skin  and  walls  of  the 
veins  make  the  blood  in  the  veins 
appear  blue,  but  it  is  dark  pur- 
plish red.  (Did  you  ever  see 
"blue"  blood?)  Place  the  tip 
of  the  middle  finger  on  one  of  the 
large  veins ;  with  the  forefinger 
then  stroke  the  vein  toward  the 
heart  so  as  to  push  the  blood  from 
a  portion  of  it,  keeping  the  two 
fingers  in  place.  The  vein  re- 
mains empty  between  the  fingers. 
Lift  the  finger  nearer  the  heart, 
and  no  blood  enters  the  vein; 
there  is  a  valve  above  which  holds 
it  back.  Lift  the  other  finger, 
and  the  vein  fills  instantly. 
Stroke  a  vein  toward  the  hand, 
and  see  the  blood  cause  the  veins 
to  swell  up  into  little  knots  where 
the  valves  are.  (Experiments 
upon  veins  are  plainest  with 
adults,  whose  veins  are  large.) 
The  veins  have  valves  placed 
frequently  along  their  course. 
The  valves  are  pockets  made  by 
a  fold  in  the  inner  coat  of  the  wall  of  the  vein  (Fig.  137). 
When  you  place  your  hand  in  your  pocket,  the  latter  swells 


FIG.  136.  —  The  veins  near 
the  surface  on  the  arm.  Nerves 
may  be  seen  accompanying  the 
veins.  The  fibrous  sheaths 
covering  most  of  the  muscles 
have  not  been  removed.  The 
veins  of  the  first  three  fingers 
are  not  shown. 


The  Circulation  of  the  Blood 


237 


out ;  but  if  you  rub  your  hand  on  the  outside  of  the  pocket 
from  the  bottom  toward  the  top,  it  flattens  down.     So  with 
the  action  of  the  blood  upon  the  valves    ====== 

in  the  veins  (Figs.  138,  139).     They  all   c        ^     >        H 
open  toward  the  heart.     The  valves  sup-  ~~A 

port  a  column  of  blood  in  each  vessel 
and  this  support  is  very  valuable  in  re- 
turning the  venous  blood  from  the  legs. 

By  exercise. — Suppose  a  muscle  hardens      FIG.  137.— Diagram 
as  it  contracts  and  presses  upon  a  vein  of  the  valves  of  veins. 

...  A,    H,    heart      side  ; 

Which  goes  through  the    C,  capillary  side. 


muscle;    the   blood   is 


The 

arrow  shows  the  direc- 
tion of  flow.     B,  The 
pressed  OUt  Of  the  Vein.    valve     prevents     the 

The   blood    cannot   go  ^°Jdfrom  going  back" 
toward  the  capillaries, 
for  the  valves  fill  and  close  when  it  starts 
that  way;  so  it  is  all  pressed  out  toward 
the  heart.     When  the  muscle  relaxes,  the 
blood    that    has    been    pressed    forward 
FIG.  138.—  Valve    cannot  come  back  because  of  the  valves, 
but  the  valves  nearer  the 
capillaries  open,  and  the 
When  the  muscle  contracts 

again,  the  same  effect  on  the  blood  move- 

ment is  repeated.     We  see,  therefore,  that 

every  contracting  muscle  acts  like  a  pump 

forcing  the  blood  through  the  veins,  and 

when  a  person  works  or  exercises,  many 

pumps  of  a  muscular  kind  are  working  all 

over  the  body,  aiding  the  heart  in  its  func- 

tion (Fig.  140).     This  aid  makes  the  blood 

flow  faster  and  relieves  the  heart  of  part  of 

its  work,  so  that  it  beats  faster,  just  as  a 

horse  might  trot  faster  if  half  the  load  were  removed.     All 

of  the  body  gets  fresher  blood  than  it  got  when  the  muscles 


veins  are  filled. 


FlG-  i39.-Vein 


Healthful  Living 


were  still  and  the  blood  flowed  more  slowly.     This  help 

comes  during  active  work,  just  when  the  body  is  demanding 

more  blood  and  the  heart  needs  help. 

By  the  lungs.  —  On  inspiration  *  the  lungs  help  to  circulate 

the  blood,  since,  when  they  expand  and  the  air  rushes  into 

them,  the  blood  as 
well  is  drawn  to- 
ward the  cavity  of 
the  chest. 

Does  the  elas- 
ticity of  the  arterial 
wall  furnish  any 
force  to  aid  the 
heart?  No.  When 
the  arteries  con- 
tract as  the  pulse 
passes,  it  is  the 
force  of  the  heart 
that  is  doing  it. 
When  you  open  a 
door  or  gate  that  is 
closed  by  an  elastic 
spring,  it  is  the 
force  furnished  by 
you  to  the  spring 
that  shuts  the  door 

FIG.  140. -Diagram   showing  effect  of  mus-  after     y°U      release 

cular  contraction  upon  venous  circulation.     The  your  hold, 

valves  prevent  the    blood   from  flowing  in  two  *      R      <mn**nnP    n<nrl 
directions ;   it  can  only  flow  toward  the  heart.  D9    '        SaQe 

position.  —  So  effec- 
tive and  necessary  is  exercise  in  aiding  the  circulation,  that 
some  people  employ  others  who  are  skilled  in  the  art  called 
massage,  to  come  regularly  and  squeeze  and  knead  every 
muscle  like  dough.  Thus  fresh  blood  is  brought  and  the 
removal  of  waste  material  from  the  tissues  is  aided.  This 


~*\~Contractect 


VatveofVein 


The  Circulation  of  the  Blood  239 

will  remove  waste  material,  but  such  a  person  misses  the  tonic 
effect  on  the  nervous  system  that  comes  from  participating 
in  sports  and  activities  with  other  people.  The  artificial 
makeshifts  of  man  never  include  all  that  Nature  would  give. 

The  arteries  lie  deep  under  the  muscles  near  the  bones, 
and  are  likewise  pressed  upon  by  muscles,  but  their  walls 
are  much  stiffer  than  the  walls  of  the  veins.  In  fact,  many 
of  them  in  passing  through  the  muscles  have  tough,  fibrous 
sheaths.  It  is  well  that  the  arteries  are  not  so  much  af- 
fected by  exercise,  for  if  they  were  squeezed  by  the  con- 
tracting muscles,  the  blood  would  be  pressed  backward  as 
well  as  forward  since  they  are  destitute  of  valves,  and  this 
would  not  be  favorable  to  the  circulation. 

So  called  "  growing  pains  "  in  a  child  are  due  often  to 
exposure  to  cold  and  wet  or  to  falling  arches  in  the  feet. 
These  pains  may  come  from  overfatigue  or  may  be  a  slight 
form  of  rheumatism.  The  feet  should  be  examined  and  if 
at  fault  the  proper  treatment  should  be  given.  Massage  of 
the  muscles  and  parts  after  overwork  is  beneficial  and  useful. 

Position  of  the  body  may  aid  the  flow  of  blood  by  over- 
coming the  action  of  gravity  in  the  large  vessels  of  the  legs. 
The  circulation  will  be  assisted  by  assuming  a  lying  position. 
After  a  long  walk,  or  tiring  exercise,  the  circulation  will  be 
aided  by  elevating  the  feet  and  legs. 

The  lymphatic  circulation.  — The  lymphatic  *  system  com- 
prises lymphatic  vessels  distributed  over  the  entire  body, 
glands  located  in  large  numbers  throughout  the  body,  es- 
pecially in  the  groin  and  in  the  armpit,  and  the  spleen,  whose 
exact  function  is  unknown  but  whose  structure  is  lymphatic 
in  character. 

How  the  nourishment  gets  from  the  blood  into  the  tissues.  — 
We  left  the  food  and  oxygen  in  the  capillaries.  How  does 
it  get  out  of  them  into  the  tissues?  We  found  that  the 
blood  flows  very  slowly  in  the  capillaries  (-£$  of  an  inch  per 
second),  and  that  the  capillary  walls  are  very  thin,  being  made 


240 


Healthful  Living 


of  only  the  inner  of  the  three  coats  that  make  the  veins  and 
arteries.  Here,  then,  are  two  favorable  conditions  for  giv- 
ing up  the  nutrition  (Fig.  141).  We  learned  that  the  protein, 
carbohydrates,  and  fats  were  dissolved  in  the  plasma,  or 
liquid  portion  of  the  blood.  The  plasma  passes  through  the 
thin  capillary  walls,  carrying  the  food  with  it.  When  it  gets 
outside  the  capillaries,  it  is  next  to  the  walls  of  the  cells  that 
make  up  the  tissues.  These  spaces  are  called  lymph  spaces. 

Thus  the  lymph  *  bathes 
the  cells  in  the  nutritious 
fluid,  and  the  hungry 
cells  absorb  what  they 
need.  The  oxygen  is 
carried  in  chemical  com- 
bination with  the  haemo- 
globin of  the  red  cor- 
puscle. 

The  red  corpuscles 
bearing  the  oxygen  can- 
not get  through  the  cap- 
illary walls.  But  the 
oxygen  is  carried  also  in 
the  plasma  and  it  easily  passes  out  into  the  tissues.  The  cells 
in  the  tissues  use  up  the  oxygen  of  the  plasma  and  the  plasma 
replenishes  its  supply  from  the  red  blood  corpuscles.  Carbon 
dioxide,  which  is  one  of  the  products  of  the  combination  of 
oxygen  with  the  food  material  in  the  tissues,  is  also  a  gas. 
It  returns  to  the  heart  and  to  the  lungs  in  the  plasma  of  the 
venous  blood  and  the  lymph. 

Why  cannot  the  capillaries  themselves  carry  the  food  and 
oxygen  into  the  tissues?  Because  they  are  tubes,  and  as 
long  as  the  food  is  in  the  blood  it  cannot  reach  the -cells; 
the  capillary  walls  prevent.  The  lymph  spaces  and  the 
lymphatics  act  as  middlemen  between  the  blood  and  the 
cells  (Fig.  142). 


Vein 
Artery  • 

FIG.   141.  —  Capillaries  connecting  a 
small  artery  with  a  small  vein. 


The  Circulation  of  the  Blood 


241 


Lymph.  —  If  the  plasma  kept  coming  into  the  tissues 
without  any  way  of  getting  back  into  the  blood  vessels,  the 
blood  would  soon  be  . 

lacking  in   plasma  and  

the  tissues  would  be  op-    7***™  Ce//s j  ^ 

pressed    with    it.      We   Lymphat/c.  ^ 
see,  then,  the   absolute 
necessity  for  some  pro- 
vision to  get  this  liquid 
back     into    the     blood 
vessels,  from  which  it  is 
constantly   overflowing. 
This    is    done    by    a    system 
(Fig.  143). 

What  is  lymph? 


FIG.   142.  —  Diagram  to  show  function  of 
lymph  and  origin  of  lymphatics. 


of    tubes    called    lymphatics 


lymphatic 

of  the  right  arm. 

B 


The  blood  plasma  is  called  lymph  after 
it  gets  out  of  the  capillaries.  But  it 
soon  becomes  changed  by  the  addi- 
tion of  substances  thrown  out  by  the 
cells,  and  by  giving  up  to  the  cells  the 
digested  food  brought  by  the  blood. 
We  should  have  said  also  that  the 
white  blood  corpuscles  may  pass  out 
into  the  lymph,  especially  if  there  is 
some  condition  in  the  tissues  that 
they  can  correct  (Fig.  124). 

We  may  say,  then,  that  lymph  is 
nearly  the  same  as  the  blood  without 
the  red  corpuscles.  Did  you  ever  see 
any  lymph?  Certainly  you  have  seen 
it,  many  times.  Whenever  there  is  a 
blister  in  the  skin  from  friction,  or 
from  a  burn,  the  lymph  collects. 
Sometimes  when  the  skin  is  grazed, 
but  ™  blood  vessel  touched,  the 
lymph  may  exude. 


242 


Healthful  Living 


The  origin  and  course  of  the  lymphatics.  —  Unlike   the 
blood  vessels,  the  lymphatics,  or  the  tubes  which  carry  the 


Super/or 
Vena   Cava 


Thoracic  Duct 


Keceptocu/um 
Chy/i 


Left  Jugu/ar 
"Vein 


.Left  -Subc/av/an 
Vein 


Lymphatic 

in  Lumbar  J?e(fions\ 


FIG.  144.  —  The  thoracic  duct.  Note  the  opening  of  thoracic  duct  into 
the  junction  of  left  jugular  and  left  subclavian  veins.  The  connection 
of  these  veins  with  the  superior  vena  cava  has  been  cut  across  to  show  the 
thoracic  duct  behind  it.  The  lymphatic  glands  in  the  lumbar  region  mark 
the  beginning  of  the  thoracic  duct. 

lymph,  have  a  beginning.  The  blood  vessels  do  not  begin, 
but  make  a  never-ending  circle.  The  lymphatics  begin 
in  open  ends  between  the  capillaries  and  the  cells,  or  among 


The  Circulation  of  the  Blood  '   243 

the  cells  themselves  (Fig.  142).  It  will  be  interesting  to 
learn  how  they  lead  the  lymph  back  to  the  circulation,  and 
what  makes  it  flow,  for  surely  there  is  no  heart  for  the  lymph 
as  there  is  for  blood.  When  the  lymph  once  enters  the  open 
end  of  the  lymphatic,  it  does  not  return  to  the  blood,  but 
continues  to  move  slowly  or  at  intervals  through  the  lym- 
phatics on  its  return  to  the  blood  system  (Fig.  144).  Small 
lymphatics  come  together  and  form  larger  ones.  They 
continue  to  unite  and  form  larger  ones,  until  finally  the 
lymphatics  from  nearly  the  entire  body  unite  into  one  large 
tube,  which  passes  up  through  the  abdomen  and  thorax, 
and  pours  the  lymph  into  the  venous  system  beneath  the 
collar  bone  near  the  neck.  This  largest  of  all  lymphatics 
is  called  the  thoracic  duct. 

The  thoracic  duct  is  about  the  size  of  a  goose  quill,  and 
empties  into  the  venous  system  just  where  the  large  vein 
from  the  left  side  of  the  head  (the  left  jugular  vein)  joins 
the  large  vein  from  the  left  arm  (left  subclavian  vein) 
(Fig.  144).  We  said  the  lymphatics  from  nearly  all  over 
the  body  form  the  thoracic  duct;  but  the  lymphatics  from 
the  right  arm  and  right  side  of  the  trunk  and  head  form 
what  is  called  the  right  lymphatic  duct,  which  empties  into 
the  right  subclavian  vein  just  where  the  right  jugular  vein 
joins  the  latter.  (See  Plates.) 

What  makes  the  lymph  flow.  —  Did  we  not  learn  that  some- 
thing besides  the  heart  makes  the  blood  flow?  It  is  the 
contraction  of  the  muscles  and  their  consequent  pressure 
upon  the  veins.  The  valves  in  the  veins  make  this  pressure 
effective  by  allowing  the  blood  to  be  forced  in  only  one 
direction.  It  is  likewise  found  that  the  lymphatics  have 
valves,  and  that  they  are  more  abundant  than  those  of  the 
veins.  Whenever  the  muscles  contract,  the  lymph  is  forced 
along,  and  the  valves  provide  that  no  progress  made  shall 
be  lost  by  any  backward  movement.  Every  pressure  leaves 
a  part  of  the  lymphatic  empty  and  ready  to  fill  from  behind 


244 


Healthful  Living 


(Fig.  145).     Also,  if  the  body  is  pressed  upon  or  shaken,  as 

when  riding  a  trotting  horse,  or  in  a  jolting  vehicle,  the  lymph 
is  moved  beyond  the  valves  at  every  jolt,  and 
its  circulation  aided. 

The  secret  of  the  powerful  effect  of  mus- 
cular work  upon  the  health  lies  chiefly  in  the 
great  aid  that  it  gives  the  lymphatic  and 
venous  circulations.  The  importance  of  an 
active  lymphatic  circulation  is  seen  when  we 
remember  that  the  blood  does  not  make  its 
exchange  directly  with  the  cells  of  the  tissues, 
but  with  the  lymph,  and  the  lymph  makes 
the  exchanges  with  the  tissue  cells. 

The  lymphatic  glands.  —  Along  the  course 
of  the  lymphatics,  nu- 
merous enlargements  oc- 
cur called  lymph  nodes  * 
or  lymph  glands  (Fig. 
146)  .  They  consist  of  a 
connective  tissue  frame- 
work, the  meshes  of 
which  are  crowded  with 
lymph  cells.  The  lymph 
in  its  course  must  filter 
through  these  clusters  of 

cells,  and,  in  doing  so,  is  purified  ;  for 

the  node  cells  take  up  impurities  in 

the  lymph,  and  work  over  and  change 

their  nature.     The  cells  in  these  nodes 

FIG.  146.  —  Lymphatic 

multiply,  and  some  of  them  are  taken    gland.    Showing  vaived 

up  by  the  lymph  and  carried  into  the 

blood    to    become    those    remarkable 

little  bodies,  the  white  blood  corpuscles.     It  is  a  curious 

fact  that  the  older  white  corpuscles  are  broken  up  in  the 

lymph  nodes,  and  their  Vemains  are  absorbed  by  the  newly 


FIG.  145.  — A 
full  lymphatic 
with  its  valves 
distended  (cut 
open) . 


******* 


The  Circulation  of  the  Blood  245 

formed  white  corpuscles,  just  as  the  latter  absorb  germs 
and  other  foreign  particles  that  may  enter  the  blood.  The 
lymphatics  penetrate  and  help  in  the  nourishment  of  every 
tissue,  even  in  that  of  the  bony  tissue. 

The  spleen.  —  This  organ  resembles  the  lymph  nodes.  It 
is  purplish  red,  about  five  inches  in  length,  and  is  situated 
just  inside  of  the  lower  ribs  on  the  left  side  of  the  abdomen. 
White  corpuscles  are  formed  in  it  as  well  as  in  the  smaller 
lymph  nodes.  In  it  also  the  red  corpuscles  that  have  finished 
their  service  in  the  blood  are  probably  broken  up  and  de- 
stroyed. 

Hygiene  of  the  circulation.  —  Have  you  learned  yet  the 
curious  fact  that  all  of  the  living  cells  of  the  body  live  under 
water,  just  as  the  amceba  does?  The  lymph  and  the  blood 
are  chiefly  water  and  the  cells  are  all  bathed  continually  in 
one  or  the  other.  The  blood  bathes  the  cells  in  the  walls 
of  its  vessels,  and  the  lymph,  or  the  blood  without  the  red 
corpuscles,  is  found  filling  the  interstices  or  spaces  between 
the  cells,  like  water  in  a  sponge.  From  the  spaces,  as  we 
learned,  it  is  taken  by  the  lymphatics  in  order  to  make  room 
for  fresh  lymph,  free  from  waste  material  and  bringing  fresh 
nourishment.  The  only  exception  to  the  rule  that  the  cells 
live  a  watery  existence,  is  found  on  the  surface  of  the  body ; 
the  cells  of  the  outer  skin,  hair,  and  nails,  however,  may  be 
called  dying  cells,  for  they  are  not. alive  in  the  same  sense 
that  the  other  cells  are  :  they  do  not  contain  nuclei  and  can- 
not repair  themselves  or  grow. 

The  importance  of  good  circulation.  —  The  supreme,  the 
transcendent  importance  to  the  health  of  the  tissues,  of  pure 
blood  and  good  circulation,  now  becomes  apparent.  All 
that  the  cells  need,  in  order  to  be  sound  and  vigorous,  is  to 
have  good  food  and  oxygen  brought  within  their  reach,  and 
to  have  the  waste  material,  or  products  of  combustion,  re- 
moved ;  the  circulation  meets,  these  needs. 

When  unsoundness  occurs  in  any  part  of  the  body,  there 


246  Healthful  Living 

is  a  strong  probability  that  the  circulation  there  is  defective. 
The  hair  is  lost  by  cutting  off  the  circulation  from  the  scalp. 
The  eyes  may  become  inflamed,  or  the  lids  diseased,  because 
of  obstructing  in  the  neck  the  return  of  the  blood  from  the 
head ;  improper  neck  clothing  or  stiffened  muscles  may 
cause  this  obstruction.  Indigestion  may  result  if  vigorous 
mental  or  physical  activity,  just  after  eating,  draws  the 
blood  away  and  prevents  the  secretion  of  the  digestive  fluids. 
Gout  may  occur  from  the  deposit  of  waste  materials  in  the 
spaces  around  the  joints  where  the  pressure  from  the  circu- 
lation is  least.  Colds  occur  when  the  blood  vessels  in  the 
walls  of  the  air  passages  become  congested  or  swollen  with 
blood,  and  the  vessels  lose  their  tone  so  that  they  cannot 
contract  and  keep  the  blood  moving  onward. 

Pure  blood  is  just  as  necessary  as  free  and  unimpeded 
circulation.  We  shall  learn  later  how  the  digestive  organs 
serve  to  furnish  the  nutrition,  how  the  lungs  furnish  the 
oxygen,  and  how  the  skin,  kidneys,  and  lungs  remove  from 
the  blood  the  impurities  and  waste  materials. 

Taking  cold.  —  Sudden  or  prolonged  exposure  to  cold 
while  the  muscles  are  inactive,  so  stimulates  the  surface 
blood  vessels  through  the  vasomotor  nerves  that  they  be- 
come tightly  contracted  and  send  the  blood  to  the  interior 
of  the  body.  It  accumulates  there  and  may  cause  such  con- 
gestion of  the  mucous  membrane  of  the  nose,  throat,  wind- 
pipe, or  lungs,  that  inflammation  ensues.  A  cold  is  an  in- 
flammation of  the  mucous  membrane  of  part  of  the  air 
passages.  Rapid  cooling  off  from  a  heated  condition,  es- 
pecially if  one  is  in  a  profuse  perspiration,  may  cause  the 
same  results ;  or,  exposure  to  moderate  but  continuous  cold 
without  exercising  may  bring  on  a  cold.  Sitting  on  the 
damp  ground,  sitting  with  damp  feet,  sitting  for  a  long  time 
in  a  cool  draught,  or  going  thinly  clad  in  cool  weather,  may 
cause  a  cold  ;  only  foolish  persons  think  they  are  so  hardened 
as  to  withstand  such  risks  without  injury. 


The  Circulation  of  the  Blood  247 

A  person  may  be  in  the  habit  of  coddling  himself  by  living 
in  overheated  rooms,  or  by  wearing  too  warm  clothing  and 
by  constant  use  of  mufflers  on  going  out ;  his  surface  nerves 
thus  become  so  delicate  and  the  blood  vessels  of  the  surface 
so  relaxed,  as  to  insure  taking  cold  on  every  accidental  or 
unavoidable  exposure.  A  better  plan  is  to  keep  the  house 
cool,  the  thermometer  standing  at  65°  to  68°,  sleep  with  open 
windows,  take  cool  baths,  and  keep  warm  when  out  of  doors 
by  walking  or  exercising  briskly.  Thus  the  blood  vessels 
are  toned  up,  the  circulation  is  made  vigorous  and  steady, 
and  the  person  is  better  fitted  to  withstand  the  ordinary 
conditions  of  life  without  disease  continually  recurring  owing 
to  deranged  or  weak  circulation.  Any  process  of  "  harden- 
ing to  cold  "  that  is  not  accompanied  by  vigorous  exercise 
is  a  risk  to  the  health. 

The  reciprocal  action  of  the  blood  vessels  of  the  skin  and 
the  internal  organs  is  sometimes  illustrated  when  a  person 
drinks  freely  of  cold  water.  There  is  a  sudden  breaking  out  of 
perspiration.  Why  is  this?  Certainly  the  water  does  not 
reach  the  skin  so  quickly.  The  cold  in  the  interior  stimu- 
lates the  internal  vessels  to  contraction  and  the  blood  is 
diverted  to  the  unstimulated  vessels  of  the  skin,  surrounding 
the  sweat  glands. 

Effects  of  unusual  exercise.  —  If  a  person  has  sedentary 
habits  and  has  neglected  active  exercise  for  some  time,  the 
heart,  as  well  as  the  other  muscles,  becomes  weak.  If  such 
a  person  hurries  to  catch  a  train,  or  takes  very  rapid  and 
trying  exercise  of  any  kind,  he  may  bring  on  an  unpleasant 
palpitation  of  the  heart,  which  is  a  warning  to  desist  at 
once.  Violent  exercise  should  not  be  taken  until  one  has 
gradually  led  up  to  it. 

Sleep  and  the  blood.  —  A  person  who  loses  much  sleep  be- 
comes pale ;  the  paleness  is  evidence  of  a  diminution  in  the 
number  of  red  corpuscles.  It  is  during  sleep  that  the  cor- 
puscles that  have  been  worn  out  during  the  day  are  replaced, 


248  Healthful  Living 

but  loss  of  sleep  causes  a  greater  loss  to  the  blood  than  usual, 
with  less  than  the  usual  opportunity  for  repair. 

The  influence  of  thought  and  feeling.  —  Rage  excites  and 
strains  the  heart.  The  experience  of  great  emotion,  either 
of  joy  or  anger  or  fright,  often  raises  the  blood  pressure  so 
much  that  a  vessel  is  broken  and  death  occurs.  Calmness 
and  poise*  are  mental  qualities  that  have  desirable  effects 
upon  the  circulation. 

Clothing.  —  The  blood  cannot  circulate  with  perfect 
freedom  unless  the  entire  body  is  so  loosely  clothed  that  there 
is  no  pressure  upon  any  of  the  blood  vessels,  no  interference 
with  the  lungs  as  they  expand,  no  pressure  upon  the  stomach, 
liver,  and  intestines.  Many  of  the  largest  veins,  particu- 
larly those  of  the  arms  and  legs,  lie  so  near  the  surface  that 
any  tightness  of  the  clothing  is  certain  to  diminish  the  flow 
of  blood  through  them.  Sleeve  supporters  and  garters,  if 
used  at  all,  should  be  of  weak  elastic  with  adjustable  buckle, 
and  no  tighter  than  is  absolutely  necessary.  It  is  especially 
necessary  to  keep  the  extremities  warmly  clad  and  dry. 

Injury  to  the  blood  vessels.  —  To  perform  effectively  the 
work  of  transporting  the  blood,  the  vessels  must  remain 
whole,  and  they  must  keep  their  shape  and  elasticity.  In- 
jury of  the  vessels  may  occur  by  cutting  of  the  vessel  wall 
or  by  changes  in  the  wall  so  that  it  loses  its  shape  or 
elasticity. 

Hemorrhages.  —  Hemorrhage  is  a  flow  of  blood  from  an 
injured  blood  vessel.  When  the  wound  is  slight,  the  clotting 
of  the  blood  stops  the  flow.  Clotting  is  rapid  in  the  blood  of 
healthy  persons  and  slow  in  the  blood  of  poorly  nourished 
persons.  Blood  does  not  spurt  from  a  cut  vein  but  flows  in 
a  slow  stream.  When  an  artery  is  cut,  the  blood  comes  forth 
in  a  jet,  with  stronger  spurts  at  each  throb  of  the  heart. 
In  a  large  artery  the  pressure  is  so  strong  that  it  forces  away 
the  clot  as  fast  as  it  is  formed,  so  that  death  may  result 
from  loss  of  blood. 


The  Circulation  of  the  Blood  249 

Varicose  Veins.  —  Varicose  veins  are  enlarged  and  tor- 
tuous veins.  This  condition  occurs  more  frequently  in 
people  who  take  little  exercise,  who  follow  occupations  in 
which  they  stand  still  for  long  periods,  as  motormen  and 
clerks.  Postmen  who  are  on  their  feet  a  great  deal  but  very 
active  rarely  suffer  from  varicosi ties.*  Why  is  this  so?  Has 
muscular  contraction  anything  to  do  with  the  circulation  of 
the  blood  (Fig.  140)  ?  Tight  garters  should  not  be  worn, 
because  they  prevent  the  venous  flow  by  constricting  the 
part. 

Hardening  of  the  Arteries.  —  Hardening  of  the  arteries 
occurs  in  late  adult  life  and  seems  to  be  caused  by  intemperate 
living.  Too  much  physical  work,  too  much  mental  work, 
too  much  work  for  the  digestive  organs,  may  produce  a 
hardening  of  the  arteries.  The  loss  of  elasticity  is  caused 
by  an  accumulation  of  salts  in  the  wall  of  the  artery.  The 
salts  make  the  artery  hard.  It  becomes,  therefore,  less  able 
to  adjust  to  changes  in  pressure,  and  it  will  break  more 
easily. 

The  effect  of  alcohol.  —  It  is  believed  that  the  white  cor- 
puscles are  injured  by  alcohol  in  the  blood,  and  that  they 
lose  to  some  extent  their  activity  in  attacking  poisons  and 
germs  of  disease.  This  gives  an  explanation  of  the  sus- 
ceptibility* of  drinking  men  to  germ  diseases.  Persons  ac- 
customed to  use  alcohol  are  usually  the  first  victims  of 
cholera  and  of  yellow  fever;  while  some  abstainers,  under 
constant  exposure,  remain  untouchecl.  The  white  corpuscles 
repair  cuts  and  broken  bones ;  hence  intemperate  persons 
do  not  recover  from  accidents  and  surgical  operations  as 
quickly  as  do  total  abstainers. 

The  "  tobacco  heart."  -  Tobacco,  unlike  alcohol,  does  not 
dilate  the  blood  vessels  of  the  skin ;  tobacco  users  are  often 
pale  from  want  of  blood  in  the  skin.  We  thus  see  why 
tobacco  users  develop  a  stronger  craving  for  drink  than  non- 
users,  because  the  alcohol  has,  in  some  respects,  an  effect 


250  Healthful  Living 

opposite  to  that  of  tobacco.  However,  heart  action  is 
temporarily  increased  when  tobacco  is  used.  In  the  previous 
chapter  you  learned  that  the  accelerator  *  nerves  increase  the 
heart  action  and  the  vagus  nerves  (inhibitory  *)  hold  it  in 
check.  The  vagus  is  partially  paralyzed  by  tobacco,  and  the 
heart  beats  with  more  force,  thus  exhausting  itself.  The 
pulse  of  the  habitual  user  shows  unmistakably  the  injury 
done  to  the  heart.  It  loses  the  firm  steady  beat  of  health 
and  becomes  irregular.  Most  of  the  time  its  beat  is  feeble ; 
for  a  period  its  beat  may  be  rapid  and  palpitating.  This 
condition  is  known  to  physicians  as  the  "  tobacco  heart." 

Physicians  who  have  made  a  special  study  of  the  subject, 
claim  that  one  out  of  every  four  tobacco  users  has  the  tobacco 
heart.  It  prevents  success  in  athletic  contests  and  feats 
of  strength.  It  prevents  a  large  proportion  of  the  young 
men  who  apply  for  enlistment,  from  entering  the  army. 
Knowing  the  paramount  importance  to  sound  health  of 
rich  blood  and  perfect  circulation,  we  are  not  surprised  to 
know  that  the  whole  body  is  enfeebled  by  tobacco,  and  that 
mental  as  well  as  physical  vigor  is  impaired.  Observant 
teachers  can  often  tell  which  of  the  boys  in  school  are  ad- 
dicted to  the  use  of  tobacco  from  the  comparative  inferiority 
of  their  appearance  and  from  their  indolence  of  body  and 
mind. 

Purification  of  the  blood.  —  The  impurities  of  the  blood 
are  the  waste  substances  which  result  from  the  chemical 
action  occurring  in  the  body  cells.  This  waste  material  is 
removed  from  the  body  if  the  circulation  is  adequate  and  if 
exercise  is  sufficient.  The  blood  is  freed  from  these  im- 
purities by  the  lungs,  by  the  sweat  glands  of  the  skin,  and  by 
the  kidneys.  This  process  of  blood  purification  is  natural, 
and  will  at  all  times  suffice,  if  the  individual  drinks  enough 
water,  avoids  constipation,  and  exercises  sufficiently.  There- 
fore, patent  medicines  which  claim  to  "  purify  the  blood  " 
are  never  necessary,  if  one  follows  the  natural  laws  of  health. 


The  Circulation  of  the  Blood  251 

Furthermore,  the  claim  of  purification  is  false  and  they  never 
accomplish  their  purpose.  Patent  medicines  are  made  to 
sell  and  not  to  accomplish  any  particular  result  in  the  body. 

Activity  is  the  most  necessary  condition  for  the  health 
of  a  cell.  In  every  cell  is  found  matter  in  three  conditions : 
that  which  is  actually  living,  that  which  was  recently  living, 
and  that  which  is  about  to  live  by  being  transformed  in  the 
cell.  The  transformation  from  lifeless  to  living,  and  from 
living  to  dead,  and  the  removal  of  dead  matter  must  go  on 
promptly.  Anything  which  interferes  with  this  activity 
interferes  with  the  health  of  the  cells.  When  life  is  natural 
and  complete,  all  the  organs  are  given  work  to  do  and  are 
healthy,  active,  and  strong;  there  is  a  feeling  of  buoyant 
happiness,  the  mind  is  clear,  the  will  is  firm,  and  the  man 
truly  lives.  Therefore,  pure  blood  will  be  available  for  the 
ceaseless  activity  of  the  cells  if  proper  and  sufficient  exercise 
is  taken. 

APPLIED   PHYSIOLOGY 
Exercise  I 

1.  The  main  arteries  run  down  the  middle  of  each  limb  close  to 
the  bone  on  the  side  toward  which  the  limb  bends.      Why  do  they 
have  this  position  ? 

2.  Where   is   the   thickest   wall   of   the   heart?     Why?     The 
thinnest  walls?     Why? 

3.  Why  do  we  need  warmer  covering  when  asleep  than  awake  ? 

4.  When  would  it  be  pleasant  to  throw  off  a  coat  or  cloak, 
but  imprudent  to  do  so  ? 

5.  If  the  clothing  has  been  accidentally  wet  and  the  wet  gar- 
ments cannot  be  changed  for  dry  ones  at  once,  how  can  one  keep 
up  a  good  circulation  to  prevent  taking  cold  ? 

6.  When  cold  air  strikes  it,  why  does  the  face  first  blanch  and 
then  flush? 

7.  When  a  person  is  warm-hearted  in  the  usual  sense  of  the 
term,  is  it  also  true  physiologically? 

8.  When  do  dark  veins  in  the  wrist  show  most  plainly?  'Of 
what  is  dark  blood  in  the  body  in  general  a  sign? 


252  Healthful  Living 

9.   Why  does  a  hot  foot-bath  sometimes  relieve  a  headache? 
Why  should  it  relieve  a  cold  in  the  head  ? 

10.  How  is  the  blood  purified  ? 

Exercise  II 

11.  Tight  clothing  at  the  waist  may  cause  too  much  blood  in 
what  parts?     Does  it  tend  to  make  the  circulation  sluggish  or 
active  ? 

12.  Which  is  more  compressible,  a  vein  or  an  artery?     Does  a 
tight  garter  interfere  more  with  the  flow  of  blood  to  the  feet  or 
from  the  feet  ? 

13.  Why  are  varicose  veins  so  often  found  in  the  lower  leg? 

14.  Why  may  a  sluggish  circulation  through  full  veins  in  the 
feet  as  well  as  want  of  blood  in  the  feet  cause  them  to  be  cold? 

15.  Why  are  students  very  likely  to  have  cold  feet  ? 

16.  Why  does  the  body  of  a  person  dying  by  drowning  or 
strangulation  turn  blue  ? 

17.  What  would  you  do  in  the  case  of  a  severe  wound  in  the 
absence  of  a  surgeon? 

18.  What  is  the  object  of  a  collar?     Why  is  it,  therefore,  not 
necessary  to  have  the  collar  as  high  in  front  as  behind?     Why 
is  it  unhealthful  to  have  it  so?     What  is  the  purpose  of  a  cuff? 

19.  What  is  the  most  serious  injury  of  alcohol  to  the  blood? 

20.  In  what  part  of  the  circulation  does  the  so-called  venous 
blood  flow  through  arteries? 

Exercise  III 

21.  Show  how  life  comes  by  death. 

22.  Can  any  physiological    basis  be  given  for  the  claims  of 
patent  medicine  venders  that  their  nostrums  "purify  the  blood  "? 

23.  What  vein  begins  and  ends  with  capillaries? 

24.  What  artery  takes  arterial  blood  to  an  organ  where  it  is 
still  further  purified,  yet  is  called  venous  blood  when  it  leaves 
the  organ?     (As  it  leaves  that  organ  the  blood  is  the  purest  in  the 
body.     See  Plate  VIII.) 

25.  What  keeps  the  blood  in  circulation  between  the  beats  of 
the  heart? 

26.  What  are  the  functions  of  the  capillaries  ? 

27.  Why  is  a  cool  draft  in  the  house  more  apt  to  cause  a  cold 
than  a  cool  wind  out  of  doors  ? 


The  Circulation  of  the  Blood 


253 


28.  Why  do  we  perspire  freely  after  drinking  freely  of  cold 
water  ? 

29.  What  causes  the  difference  between  the  hard  hand  of  the 
blacksmith  and  the  soft  hand  of  the  clerk? 

30.  Why  does  rubbing  wear  out  the  leather  of  the  shoe,  but 
the  friction  of  the  shoe  upon  the  toe  cause  the  skin  to  grow  thicker 
and  to  form  a  corn  ? 

31.  What  is  the  effect  upon  the  circulation  of  horseback  riding? 


LABORATORY  EXERCISES 

Experiment  1.    To  demonstrate  circulation,  vasomotor  control  and 

blood  pressure. 

Arrange  an  inverted  bell  jar  (Fig.  147)  on  a  support  and  connect 
it  with  a  series  of  glass  pipes  arranged  in  an  upright  position.     For 


_G/BSS_ 

Tubing 


~^~- Wafer— 


"Hart* Rubber-  Tubing' 


FIG.  147. 

the  connections  use  a  hard  rubber  tubing.  Before  the  last  two 
pipes  insert  a  section  of  soft  rubber  tubing  and  attach  a  clamp  which 
will  allow  graduated  pressure  to  be  made  on  this  section  of  the 
circulation.  Fill  the  bell  jar  with  water  colored  with  carmine  and 
notice  the  following : 

1.  Name  the  heart,  the  arteries,  the  capillaries,  and  the  veins. 

2.  Have  the  clamp  entirely  free  and  observe  the  effect  upon  the 
flow  of  water.     How  high  does  the  liquid  rise  in  the  tubes  ?     Mark 
the  point  in  each  case. 

3.  Close  the  clamp  down  so  that  no  liquid  flows  from  the  venous 
end.     How  high  does  the  liquid  rise  in  the  tubes  ?     In  which  tube 


254  Healthful  Living 

is  it  highest?     Is  this  the  tube  that  corresponds  with  the  arteries 
nearest  the  heart  ? 

4.  Open  the  clamp  enough  to  have  the  liquid  flow  from  the 
venous  end  in  a  slow  and  constant  stream.  Notice  the  change  in 
the  height  of  the  liquid  in  the  tubes.  What  are  the  points  of 
difference  between  the  effect  seen  in  (1)  and  (2)?  Would  you  say 
that  the  pressure  decreased  from  the  heart  to  the  capillaries  and 
that  in  the  venous  system  the  pressure  was  very  low  until  in  the  last 
tube  it  was  practically  at  zero  ? 

When  the  capillaries  are  shut  down,  what  effect  has  that  on  the 
blood  pressure?     Is  the  resistance  to  the  flow  of  blood  increased? 
How  is  such  effect  produced  in  the  .body? 
Experiment  2.    To  study  the  heart  rate  in  exercise. 

Material.  —  Watch  with  a  second  hand. 

Method  and  observation.  —  (a)  Palpate  the  pulse  in  the  radial 
and  temporal  arteries,  feel  with  the  tips  of  the  first  and  second 
fingers.  What  causes  the  pulsation?  (6)  Count  the  radial  pulse 
during  consecutive  15  second  periods  (one  quarter  minute)  and 
when  the  rate  in  any  two  successive  ones  are  alike,  take  that  rate 
as  the  rate  of  the  heart  for  the  time  and  activity.  Find  the  heart 
rate  per  minute  in  the  following : 

1.  Horizontal  position,  face  up. 

2.  Horizontal  position,  face  down. 

3.  Sitting  position. 

4.  Standing  position. 

5.  After  10  deep  knee  bendings. 
Does  the  rate  vary?     Why? 

Experiment  3.    To  study  the  heart  rate  in  respiration.* 

Material.  —  Watch  with  a  second  hand. 

Method  and  observation.  —  Count  the  radial  pulse  and  obtain 
the  rate  as  described  in  experiment    (1).     With  that  procedure 
obtain  the  heart  rate  during  the  inspiratory  phase  and  the  expira- 
tory phase.     Is  the  rate  different ?     In  which  is  it  faster? 
Experiment  4.    To  study  the  heart  rate  in  exercise  and  respiration. 

Material.  —  Watch  with  a  second  hand. 

Method  and  observation.  —  Count  the  heart  rate  in  the  standing 
position.  Perform  twenty  deep  knee  bendings  and  count  the 
heart  rate  at  once  at  the  end  of  the  exercise.  Notice  the  difference 
during  the  inspiratory  and  expiratory  phases  of  the  respiration. 


The  Circulation  of  the  Blood  255 

GLOSSARY 

Accelerator.  —  A  mechanism  that  increases  the  speed  of  an  organ. 

Applies  to  the  nerves  which  go  to  the  heart  and  increase  the 

rate  of  contraction  of  that  organ.     There  is  an  accelerator 

center. 
Expiration.  —  The  act  of  breathing  out.     It  comes  from  the  Latin, 

ex  meaning  out,  and  spiro,  to  breathe. 
Inhibitory.  —  A  mechanism  that  checks  the  activity  of  an  organ. 

The  effect  is  opposite  to  that  produced  by  the  accelerator  nerves 

or  center.     The  inhibitory  nerves  of  the  heart  are  the  vagi. 
Inspiration.  —  The  act  of  breathing  in.     Its  derivation  is  similar 

to  the  derivation  of  expiration. 
Lymph.  —  The  fluid  that  bathes  the  cells  and  lies  in  the  spaces 

between  the  cells.     It  is  carried  to  the  heart  by  the  lymphatics. 

It  is  derived  from  the  plasma  of  the  blood. 
Lymphatic.  —  A  tube  composed  of  thin  cells  and  serving  to  carry 

the  lymph  from  the  cell  and  tissue  spaces  back  to  the  heart. 
Lymph    nodes.  —  Small  glandular   structures   situated    along    the 

course  of  the  lymphatics  and  especially  numerous  at  the  joints. 

They  serve  to  take  out  of  the  lymph,  poisons  that  would  injure 

the  body. 

Poise.  —  Balance,  equilibrium. 

Respiration.  —  The  act  of  taking  in  and  breathing  out  air. 
Susceptibility.  —  The  condition  of  yielding  or  succumbing  readily. 

Resistance  is  the  opposite  quality.     One  who  has  little  resist- 
ance shows  susceptibility. 
Varicosity.  —  A  condition  in  which  the  veins  are  dilated,  twisted, 

and  tortuous. 


CHAPTER  XIV 
THE    RESPIRATION 

I.    Why  Breathing  Organs  are  Needed. 
II.    The  Respiratory  Organs. 

The  nose,  throat,  larynx,  and  trachea 

Bronchial  tubes 

Lungs 

The  diaphragm  and  other  muscles 
III.     The  Breathing  Process. 

Inspiration 

Expiration 

Ease  in  breathing 
IV.    The  Air  We  Breathe. 

Composition  of  the  air 

Foul  and  fresh  air 
V.   The  Hygiene  of  Respiration. 

Breathing  through  the  nose 

Muscular  action  in  breathing 

Respiratory  exercises 

Ventilation 

The  effect  of  tobacco  on  the  respiratory  organs 

General  considerations 


Why  breathing  organs  are  needed.  —  Every  cell  in  the 
body  requires  oxygen  to  enable  it  to  do  its  appointed  work. 
When  the  supply  of  oxygen  stops,  the  activity  of  the  cell 
ceases  at  once.  If  it  is  a  muscle  cell,  motion  can  be  generated 
in  the  muscle  only  by  the  union  of  oxygen  with  the  contents 
of  the  cell.  If  it  is  a  gland  cell,  it  cannot  do  its  work  of  se- 
creting useful  fluids  without  the  help  of  oxygen,  for  the  sub- 
stances which  the  gland  cell  takes  from  the  blood  must  be 

256 


The  Respiration  257 

changed  to  form  the  secretion.  If  the  cell  is  a  brain  cell, 
although  it  may  not  use  as  much  as  a  muscle  cell  uses,  oxygen 
is  still  indispensable.  The  oxidation  that  takes  place  in  the 
various  cells  results  in  the  formation  of  carbon  dioxide  and 
other  waste  products  which  would  destroy  the  life  of  the  cell 
if  allowed  to  remain;  these  are  removed  from  the  body  by 
the  same  organs  that  supply  the  oxygen.  How  does  the 
amoeba  get  its  oxygen  ? 

The  respiratory  organs.  —  It  is  obvious  that  in  animals  of 
large  size  with  many  tissues,  the  great  majority  of  the  living 
cells  of  the  tissues  must  be  buried  deep  away  from  the  ex- 
ternal surface.     But  even  if 
deep-seated  and  away  from 
the  air,  the  living  cells  have 
the  same  need  of  oxygen  as 

,  ,  ff  Lobvte l^fXKiry  ;•=?¥- Lobule 

though  near  the  surface.     If 


oxygen  is  supplied  to  the 
blood,  the  latter  conveys  the 
oxygen  to  the  cells ;  but  it 
is  seen  that  a  very  efficient 
organ  is  needed  to  supply 
the  blood  with  oxygen  suffi-  FIQ  U8  _  Two  ,obules  at  the 

cient  for  SO  many  cells.      The  end  of  a  bronchial  tube. 

breathing    apparatus    varies 

in  different  animals ;  (1)  it  usually  consists  of  a  device  for 
exposing  to  the  air  a  great  amount  of  thin  tissue,  which 
is  a  specialized  form  of  the  outer  skin  of  the  animal  (if  the 
animal  is  not  a  land  animal,  the  tissue  is  exposed  to  the  water) ; 
(2)  the  animal  is  further  provided  with  means  to  keep  up  a 
current  of  air  (or  water)  on  the  outside  of  this  modified  skin 
and  a  current  of  blood  on  the  inside.  Large  animals  with 
many  deep-seated  and  inaccessible  cells  require  for  suf- 
ficient oxygen  a  large  respiratory  area.  This  is  provided  by 
having  it  folded  as  indicated  in  Figure  148.  In  man,  it  has 
been  estimated  that  by  the  finer  and  finer  division  of  the  air 


258 


Healthful  Living 


sac,  a  pair  of  human  lungs  presents  to  the  air  a  surface  of  at 

least  one  hundred  square  feet  (or  ten  feet  square) ;  (3)  the 

remainder  of  the  breathing  apparatus  consists  of  muscles 

for  changing  that  air  that  is  in  contact  with  this  great  surface. 

Nose,  throat,  larynx,  and  trachea.  —  The  air  usually  passes 

in  at  the  nose  and  returns  by  the  same  way,  except  during 

/A/Ml  talking    or    singing. 

ThyroM  Cartilage VlSf    \-Larynx  If    ?™    lo°k   ln   y°UI* 

fc      J      '  mouth  with  a  mirror, 

you  will  see  at  the 
back  part  an  arch 
which  is  the  rear 
boundary  line  of  the 
mouth.  Just  above 
the  arch  is  likewise 
the  limit  for  the  back 
part  of  the  nasal 
passages.  The  fun- 
nel-shaped cavity 
beyond,  into  which 
both  the  mouth  and 
nasal  passages  open, 
is  called  the  pharynx 

FIG.    149.  —  Not  all  of  the  divisions  of  the  r        ' 

bronchi  are  shown,  but  notice  how  these  tubes  (far  inks),  Or  throat, 

by  the  finest  branches  extend  to  all  parts  of  the  Below        two      tubes 

Jungs.  ' 

open  from  the  phar- 
ynx, one  into  the  trachea  (trak'e-a)  or  windpipe,  the  other 
into  the  esophagus,  or  gullet.  At  the  top  of  the  trachea 
(Fig.  149)  is  the  cartilaginous  larynx,  or  voice  box,  and  the 
opening  from  the  throat  is  provided  with  a  lid,  the  epi- 
glottis, also  consisting  of  cartilage.  The  larynx  will  be 
described  more  fully  in  treating  of  the  voice ;  it  may  be 
felt  as  the  Adam's  apple.  Just  below  it  comes  the  trachea 
proper  which  is  a  tube  about  three  fourths  of  an  inch  in 
diameter,  and  about  four  inches  long  (Fig.  149).  It  con- 


The  Respiration  259 

sists  of  hoops  of  cartilage  which  are  not  complete  circles 
but  are  shaped  somewhat  like  the  letter  C,  being  com- 
pleted behind  by  nonstriated  (involuntary)  muscular  tissue, 
whose  function  is  to  draw  the  ends  of  the  rings  together  at 
times,  e.g.  during  coughing,  and  reduce  the  caliber  of  the 
tube.  The  function  of  the  hoops  of  cartilage  is  to  keep 
the  windpipe  open  at  all  times.  If  it  should  collapse  under 
pressure,  life  might  be  lost.  These  rings  of  cartilage  may 
be  felt  in  the  neck. 

Bronchial  tubes.  —  The  lower  end  of  the  trachea  is  just 
behind  the  upper  end  of  the  sternum;  and  there -it  divides 
into  two  bronchi,  called  the  right  bronchus  and  the  left 
bronchus  (plural,  bronchi).  The  bronchi  subdivide  into  a 
great  number  of  smaller  branches,  called  bronchial  tubes. 
Cartilage  is  found  in  the  walls  of  all  but  the  smallest  of  the 
tubes.  The  subdivision  continues  until  the  whole  lung  is 
penetrated  by  branches,  all  having  the  general  name  of 
bronchial  tubes  (Fig.  149).  The  smallest  are  only  about  ^ 
of  an  inch  in  diameter.  They  ramify  through  the  lungs, 
somewhat  like  the  branching  of  a  tree,  each  tiny  tube  finally 
ending  in  a  wider  funnel-shaped  chamber  called  a  lobule 
(Fig.  148),  into  which  so  many  dilated  sacs,  called  air  cells, 
open  that  the  walls  of  the  terminal  chamber,  or  lobule,  may 
be  said  to  consist  of  tiny  cups,  or  air  cells,  placed  side  by 
side.  (The  word  "  cell  "  is  here  used  in  its  original  sense  to 
denote  a  cavity  or  chamber,  and  not  in  the  sense  of  a  proto- 
plasmic cell.) 

Lungs.  —  The  lungs  are  elastic  air-containing  organs 
constructed  of  epithelial  cells  of  several  kinds  and  blood 
vessels.  The  air  cells  are  arranged  to  allow  air  to  come 
readily  into  contact  with  the  blood,  and  to  remove  from  the 
lining  the  dust  and  dirt  that  has  come  in  with  the  air.  The 
numerous  blood  vessels  afford  means  of  rapidly  moving  the 
blood  through  the  lungs.  The  elastic  nature  of  the  lungs 
provides  for  easy  and  quick  inflation.  These  characteristics 


26o 


Healthful  Living 


FIG.  150.  -?-The  wall  of  an 
air  cell,  a,  the  epithelium ; 
b,  partition  between  two  air 
cells,  in  which  the  capillaries 
lie ;  c,  fibers  of  elastic  tissue. 
Notice  b,  and  name  the  struc- 
tures through  which  oxygen 
and  carbon  dioxide  must 
pass. 


are  best  understood  by  studying  the  internal  and  external 

structure. 

Internal  Structure.  —  The  wall  of  an  air  cell  consists  of 

elastic  connective  tissue  lined  with  a  layer  of  very  flat  and 
thin  epithelial  cells  (Fig.  150).  This 
lining  is  continuous  with  the  epi- 
thelial lining  of  the  bronchial  tubes. 
It  is  so  thin  as  to  offer  almost  no 
obstruction  to  the  passage  of  oxy- 
gen out  of  the  cell  and  the  entrance 
of  the  carbon  dioxide  from  the  blood 
vessel  (Fig.  151). 

It  must  be  remembered  that  mu- 
cous membrane  lines  all  cavities  in 
the  body  accessible  to  the  air.  Al- 
most all  of  the  nose  and  pharynx, 
and  all  of  the  trachea  and  bronchial 

tubes,  as  far  as  the  lobules,  are  lined  with  a  mucous  mem- 
brane the  cells  of  which  are  furnished  with  cilia  (Fig.  152). 

These  are  minute  hairlike  filaments  which  are  in  constant 

motion.     When  a  few  of  the  cells  are  examined  under  a 

microscope,     we 

may  see  the  cilia 

in  motion,  even 

for  a  time  after  sma/t Arteries 

the    removal    of 

the  cells  from  the 

body.       They 

make     a    quick 

stroke     upward, 

and  move   back 

more  slowly,  and 

this  is  found  to 

give    them    the 

power  of  moving 


and  Veins 


Network  of_ 
CapiJ/arfes 


FIG.   151.  —  The  blood  vessels  around  two  air  cells. 


The  Respiration 


261 


particles  of  dust  which  enter  the  lungs  upward  toward  the 
larynx.  Upon  reaching  the  larynx,  the  dust  brings  about 
irritation  which  causes  it  to  be  coughed  up.  In  the  nasal 
passages,  they  serve  a  similar  purpose.  At  the  opening  of 
the  nostrils  are  also  placed  ordi- 
nary hairs  (hundreds  of  times 
larger  than  cilia),  which  aid  in 
cleaning  the  air  of  dust  as  it 
enters  the  nose. 

Near  where  the  trachea  divides 
into  the  two  bronchi,  the  pulmo- 
nary artery,  bringing  the  dark  blood 
to  the  lungs,  divides  into  two 
branches,  and  the  subdivision  con- 
tinues, until,  finally,  a  network  of 
capillaries  is  formed  around  each 

lobule,  or  cluster  of  air  cells.    These 

'  FIG.     152.  —  Ciliated     cells 

Capillaries   are    the    termination    Of    from  the  trachea  of   a  rabbit, 

the    branches   of    the   pulmonary   hiehly  magnified,    a,  b  c.  mu- 

cous  cells  in  various  stages  of 

artery,  and  the  beginning  of  the   secreting  mucus, 
pulmonary  veins.     It  is  here  that 

the  blood  changes  from  a  purplish  red  to  a  scarlet  red.  A  fine 
connective  tissue  holds  together  all  these  air  cells  and  tubes. 
External  Appearance.  —  The  entire  cavity  of  the  chest 
except  the  space  occupied  by  the  heart  and  a  few  of  its  blood 
vessels  and  the  esophagus,  is  filled  by  the  lungs  and  their 
coverings.  The  lungs  are  light  pink  in  early  life  but  become 
grayish  and  darker  as  age  advances.  This  change  is  more 
marked  in  persons  who  dwell  in  large  cities  or  where  the  at- 
mosphere is  smoky  and  dusty.  The  lungs,  or  a  part  of  one, 
will  float  if  thrown  upon  water.  The  right  lung  has  three 
lobes,  or  divisions,  and  the  left,  two  lobes.  The  general 
substance  of  the  lungs  consists  of  bronchial  tubes,  blood 
vessels,  lymphatics,  and  air  cells,  as  above  described,  the 
air  cells  being  chiefly  near  the  surface. 


262  Healthful  Living 

The  surface  of  the  lungs  is  in  contact  with  the  chest  wall, 
but  it  is  not  attached  to  the  chest  wall.  It  is  held  in  con- 
tact by  the  negative  pressure*  within  the  chest  cavity.  This 
negative  pressure  during  respiration  varies  from  755.5  mm. 
of  mercury  on  expiration  to  752.5  mm.  of  mercury  on  in- 
spiration. Its  negativity  therefore  increases  during  inspira- 
tion. Imagine  a  closed  bag  or  sac  made  of  thin  membrane 
lining  the  whole  of  the  chest.  Now  imagine  another  closed 
sac  a  little  smaller,  that  is  inside  of,  and  lining,  the  first  one. 
Next  imagine  the  lungs  to  be  found  inside  the  inner  sac.  Here 
we  have  the  lungs  within  the  two  membranes,  called  the 
pleuras.  The  pleuras  are  in  contact,  so  that  the  lung  may  be 
said  to  be  in  contact  with  the  chest  wall. 

The  outer  pleura  lines  the  chest  wall,- the  inner  pleura  covers 
the  lung^.  The  two  membranes  form  between  them  a  closed 
sac,  a  serous  cavity  which  is  air-tight  and  aids  the  lungs  in 
following  the  chest  wall  without  friction  when  the  chest  ex- 
pands. The  two  pleura!  surfaces  are  in  contact,  and  secrete 
just  enough  fluid  to  enable  them  to  glide  smoothly  upon 
each  other.  But  for  the  pleura  there  would  be  friction  be- 
tween the  lungs  and  the  chest  walls. 

The  diaphragm  and  other  muscles  (Fig.  153).  —  The  floor 
of  the  chest  cavity  is  formed  by  a  muscle  that  is  the  broadest 
in  the  body,  and  also  the  thinnest -in  proportion  to  its  width. 
It  is  called  the  diaphragm.  It  rounds  up  under  the  concave 
base  of  the  lungs  somewhat  like  a  dome  and  separates  the 
thoracic  and  abdominal  cavities.  It  is  attached  to  the 
lowest  ribs  at  the  sides  and  to  the  lumbar  vertebrae  behind 
(Fig.  153).  Its  rounded  side  is  turned  toward  the  chest, 
and  its  hollow  side  toward  the  abdomen.  It  is  the  most  im- 
portant muscle  of  the  respiratory  system.  When  it  con- 
tracts, it  flattens  and  descends,  and  the  lungs  descend  with 
it,  thus  lengthening  and  enlarging  the  cavity  of  the  chest 
from  top  to  bottom. 

When  the  diaphragm  descends,  it  acts  as  a  piston  or  a 


The  Respiration 


263 


tight-fitting  round  board  would  act  if  pressed  down  into  a 
barrel  of  water.     If  there  were  two  holes  in  the  board  (cor- 


Infer/or   Vena  Cava 


Diaphrej, 


Sternum 


'Kibs 


D/aphracfm 
Afuscu/ar  Pi//ars 
of  the  Ztfaphraqm 


Esophagus 
^Aorta 
Spfna/  Column 


FIG.  153.  —  The  dome-shaped  diaphragm.     Name  the  large  tubes 
which  pass  through  the  diaphragm. 

responding  to  the  vena  cava  and  the  thoracic  duct),  the 
water  would  be  pressed  up.     Thus  the  circulation  is  aided 


Vertebra/  Column 
Mb 


Outer  Intercosta^ 
Musc/es 


•Rib  Cartilage 


Sternum 


Inner  Intercostal^, 
Muscles 


FIG.  154.  —  Figure  A,  showing  three  ribs,  their  attachment  to  spine  and 
sternum,  and  the  muscles  completing  the  thoracic  wall.  In  B.  the  struc- 
tures between  the  intercostals  are  shown. 


264  Healthful  Living 

by  breathing.  When  the  diaphragm  relaxes,  its  thinness  and 
flexibility  would  allow  it  to  drop  downward,  instead  of  spring- 
ing upward  as  pupils  sometimes  suppose ;  but  the  abdominal 
walls  contract  as  the  diaphragm  relaxes  and  force  the  liver, 
stomach,  etc.,  against  the  diaphragm,  thus  pressing  it  against 
the  lungs  (Figs.  155,  156). 

The  chest  walls  can  be  lifted  out  at  the  sides  and  in  front. 
This  is  accomplished  by  muscles  leading  from  the  shoulders 
and  spinal  column  to  the  outer  surface  of  the  ribs,  and 
by  the  intercostal  muscles,  or  the  muscles  that  connect 
each  rib  with  the  rib  above  (Figs.  154).  Thus  the  chest 
may  be  made  deeper  from  front  to  back  and  from  side  to 
side,  and  if  the  diaphragm  acts  at  the  same  time,  the  chest 
is  elongated  from  top  to  bottom,  and  thus  is  enlarged  in  all 
directions. 

The  breathing  process.  —  The  breathing  process  serves 
to  carry  into  the  lungs  oxygen  for  the  blood  and  to  expel 
the  excess  carbon  dioxide  given  up  to  lung  air  by  the  blood. 
The  passing  of  the  air  into  the  lungs  is  called  inspiration,  and 
the  passing  of  the  air  out  from  the  lungs  is  called  expiration. 
The  two  together  constitute  respiration,  or  breathing. 

Inspiration.  —  The  lungs  themselves  contain  no  muscular 
tissue,  and  therefore,  they  cannot  expand  by  any  force  of 
their  own.  Yet  they  expand  when  the  chest  expands.  How 
does  the  enlargement  of  the  chest  cause  the  lungs  to  expand, 
and  the  air  to  rush  in?  The  air  cannot  be  pulled  in,  for  it 
has  no  cohesion,  its  parts  do  not  stick  together.  It  is  found 
that  the  air  has  considerable  weight,  for  the  height  of  the  at- 
mosphere* is  at  least  forty  miles,  and  the  air  above  is  pressing 
down  on  that  below.  When  the  chest  walls  are  moved  out- 
ward against  the  weight  of  the  outer  air  (Figs.  155,  157),  the 
space  in  the  chest  is  increased,  and  the  air  already  in  the  chest 
expands  to  fill  the  greater  space.  The  air,  when  expanded, 
is  lighter,  and  exerts  less  pressure  than  before,  and  the  denser 
air  outside,  having  greater  pressure,  presses  inward  until  the 


The  Respiration 


265 


air  in  the  lungs  is  as  dense  as  it  was  before  the  lungs  were 
enlarged.  Thus  do  we  allow  the  air  to  come  into  our  lungs ; 
we  do  not  draw  it  in  but  make  space  for  it,  and  the  atmos- 
phere outside  presses  it  in. 

Expiration.  —  This   is   the   reverse   of  inspiration.     The 
space  within  the  chest  is  diminished,  and  the  air  in  the  lungs 


Trachea 


Sternum 


Thachea 


Sternum 


FIG.   155.  —  Inspiration. 


FIG.   156.  —  Expiration. 


Diagrams  to  show  the  positions  in  respiration  of  the  sternum,  diaphragm, 
and  abdominal  wall. 

is  compressed  and  becomes  denser  than  the  air  outside.  This 
denser  air  has  greater  pressure  than  the  outside  air,  and 
presses  out  through  the  air  passages  until  enough  has  passed 
out  to  restore  the  equilibrium,  making  the  pressure  equal 
without  and  within  (Fig.  156). 

In  ordinary  quiet  expiration,  the  lungs  become  smaller, 
owing  chiefly  to  the  elasticity  of  the  parts  involved.  •  When 
the  air  rushes  in  during  inspiration,  it  fills  the  enlarged 


266 


Healthful  Living 


air  cells  and  the  walls  being  made  parity  of  elastic  tissue, 
the  cells  contract  again  when  the  muscles  of  inspiration 
cease  to  act.  When  the  ribs  are  lifted  up  during  inspira- 
tion, the  costal  cartilages  that  connect  them  with  the 
sternum  are  slightly  bent,  and  the  elasticity  of  these  carti- 

lages, as  well  as  the  weight 
of  the  chest  wall,  causes  the 
ribs  to  become  lower  when 
the  muscles  of  inspiration 
cease  to  act.  Many  pupils 
get  the  erroneous  idea  that 
the  diaphragm  is  also  elastic 
and  pushes  upward  when  it 
relaxes,  thus  aiding  expira- 
tion. When  relaxed,  it  has 
no  more  elasticity  than  a 
piece  of  cloth,  and  no  power 
to  push  itself  upward.  It 
should  be  remembered  that 
muscles  never  push  ;  they 
•always  pull  by  drawing  their 


FIG.   157.  —  Diagram  of  first  and 


origin  *  and  insertion  *  nearer. 

.         . 

seventh  ribs,  in  connection  with  the     However,    the    abdomen    has 
spine  and  the  sternum,  showing  how 
in  inspiration  the   latter   is  carried 
upward  and  forward.     The  expira- 


somewhat     Compressed, 
.  .  , 

and       its       Walls       Somewhat 

tory  position  is  indicated  by  con-    stretched  during  the  inspira- 

tinuous    lines,    the    mspiratory    by       . 

broken  lines.  tion.     When  the  diaphragm 

relaxes,  the  elasticity  of  the 

muscular  walls  of  the  abdomen  presses  the  organs  against 
the  under  side  of  the  diaphragm,  pressing  that  in  turn  against 
the  base  of  the  lungs,  and  aiding  expiration. 

Quiet  or  passive  expiration  is,  therefore,  a  rebound  brought 
about  by  the  elasticity  of  the  air  cells,  costal  cartilages, 
and  abdomen,  and  by  the  weight  of  the  chest  wall.  Active 
expiration  adds  muscular  contraction  to  the  above  forces. 


The  Respiration 


267 


The  two  layers  of  intercostal  muscles  are  among  those 
used  in  inspiration  and  active  expiration  (Fig.  158). 
When  the  upper  ribs  are  held,  the  contraction  of  the 
intercostals  raises  the  ribs;  when  the  lower  ribs  are 
fixed,  the  contrac- 
tion depresses  the 
ribs.  The  'inter- 
costals act  to  raise 
or  depress  the  ribs, 
depending  upon 
the  fixation  of  the 
ribs  above  or  be- 
low. In  active 
expiration  the  ab- 
dominal walls  con- 
tract and  press 
the  abdominal  or- 
gans against  the 
diaphragm,  thus 
pressing  upward 
on  the  lungs. 

Ease  in  breathing.  —  By  studying  the  skeleton  of  the  chest, 
carefully  observing  the  bones  and  cartilages,  and  by  ex- 
perimenting upon  his  or  her  own  breathing,  the  pupil  is 
to  fill  out  the  following  reasons  why  expansion  and  con- 
traction of  the  lower  chest  (abdominal  breathing)  is  easier 
than  breathing  with  the  upper  chest  (costal  breathing). 

1.  There  are  two  pairs  of ribs  below,  while  there  are 

none  above. 

2.  There  are  three  pairs  of  -  —  ribs  below,  while  there 

are  none  above,  but  all  the  ribs  of  the  upper  chest  are 

ribs. 

3.  The  joints  between  the  seven  pairs  of  true  ribs  and  the 
sternum  are  more  flexible  below  because  -    — . 

4.  In  abdominal  breathing  the  breaths  will  not  have  to  be? 


FIG.  158.  —  Diagram  to  show  action  of  inter- 
costal muscles  on  inspiration  and  expiration.  At 
A  two  ribs  (a-b  and  d-c)  are  represented  in  passive 
position.  The  two  ribs  move  at  the  fixed  points, 
6  and  c.  When  the  ribs  are  raised  notice  that  the 
line  a— d,  which  represents  the  sternum,  is  farther 
from  the  spine  b— c,  as  in  C,  and  nearer  when  de- 
pressed, as  in  B.  This  obliquity  of  the  ribs  per- 
mits the  increase  in  the  depth  of  the  chest  on 
inspiration  and  decrease  in  expiration. 


268  Healthful  Living 

so  frequent  to  supply  the  same  amount  of  air,  because  the 

lower  chest,  besides  being  more  flexible,  is  than  the 

upper  chest. 

5.  The  bones  of  the rest  upon  the  upper  chest.  In 

upper  chest  breathing  their  weight,  and  the  weight  of  both 
of  the ,  must,  therefore,  be  lifted.  (Test  by  experiment.) 

The  air  we  breathe.  —  Air  is  composed  of  a  mixture  made 
up  chiefly  of  oxygen,  nitrogen,  and  a  very  small  quantity  of 
carbon  dioxide.  Nitrogen  is  colorless,  tasteless,  and  odorless  ; 
it  does  not  support  combustion,  and  is  one  of  the  most  in- 
active gases  known  to  chemists.  The  oxygen  of  the  air  is 
also  colorless,  tasteless,  and  odorless,  but  it  is  one  of  the 
most  active  gases  known  to  chemists.  The  air  exhaled  con- 
tains about  the  same  amount  of  nitrogen  as  that  inhaled, 
but  it  contains  much  less  of  oxygen,  the  latter  having  been 
replaced  by  an  almost  equal  quantity  of  carbon  dioxide. 

Composition  of  the  air.  —  One  hundred  parts  of  pure  air 
contain  about  20  parts  of  oxygen,  nearly  80  parts  of  nitro- 
gen (and  other  gases),  and  .04  of  a  part  of  carbon  dioxide. 
Air  coming  from  the  lungs  contains  16  parts  of  oxygen,  nearly 
80  parts  of  nitrogen,  and  over  4  parts  of  carbon  dioxide.  The 
air  while  in  the  lungs  has  lost  4  parts  of  its  oxygen,  there 
has  been  no  essential  change  in  the  quantity  of  nitrogen, 
and  it  has  gained  4  parts  of  carbon  dioxide.  The  oxygen 
is  in  the  air  in  order  to  supply  an  element  to  animals  essential 
to  their  activity.  The  nitrogen  in  the  air  is  not  used  in  the 
body.  The  small  amount  of  carbon  dioxide  in  the  air  sup- 
plies the  plants  with  carbon.  Its  quantity  is  being  con- 
stantly added  to  by  fires  and  by  the  breath  of  animals.  The 
leaves  of  plants,  aided  by  the  sunlight,  are  constantly  re- 
moving it,  so  that  it  is  kept  at  .04  of  one  per  cent  in  the  air. 

Foul  and  fresh  air.  —  It  has  been  believed  for  many  years 
that  the  cause  of  bad  air  was  the  presence  of  carbon  dioxide 
coming  from  the  lungs.  At  one  time  it  was  supposed 
that  the  air  of  crowded  rooms  contained  an  unknown  poison. 


The  Respiration  269 

To-day,  because  of  many  studies,  it  is  known  that  the 
carbon  dioxide  plays  a  very  small  part  in  contaminating  the 
air  of  rooms  and  most  of  the  foulness  of  air  is  due  to  a  high 
temperature,*  high  humidity,*  and  lack  of  air  motion.  Fresh 
air  means,  therefore,  not  more  oxygen  or  more  "  ozone/7 
but  air  of  low  temperature,  low  humidity,  and  in  motion. 
Eastman  and  Lee  have  shown  that  the  pulse  rate  will  in- 
crease from  67  to  106  as  the  temperature  of  the  air  rises 
from  74  to  110  F.  and  the  humidity  from  68  to  90.  People 
must  recognize  these  facts  and  adopt  their  way  of  living  to 
conform  to  the  knowledge  we  have.  As  a  rule,  the  house 
is  overheated,  and  in  steam-heated  rooms  the  humidity  is 
too  high.  It  is  to  be  remembered  that  hot,  humid,  still  air 
is  to  be  avoided.  The  windows  in  the  room  should  always 
be  open  sufficient  to  allow  the  air  of  the  room  to  keep  in 
gentle  but  continuous  motion,  the  humidity  to  remain  like 
that  of  the  air  out  of  doors  and  the  temperature  not  above 
68°  F. 

The  hygiene  of  respiration.  —  Statistics*  indicate  that 
among  civilized  races  a  large  proportion  of  the  deaths  is  due 
to  lung  diseases.  This  proportion  is  frequently  estimated  as 
high  as  one  seventh  of  the  entire  number.  For  this  reason, 
it  is  important  to  care  intelligently  for  the  respiratory  system. 

The  cilia  of  the  air  passages  stop  most  of  the  dust  before  it 
reaches  the  lungs,  but  not  all.  If  the  dust  is  excessive,  mil- 
lions of  particles  enter  the  lungs.  If  a  housekeeper  would 
examine  the  air  of  the  room  with  a  beam  of  light  reflected  by 
a  mirror  during  the  time  of  sweeping,  she  would  often  be 
horrified,  and  would  heed  the  caution  of  those  who  say  that 
every  door  and  window  should  be  opened  before  beginning  to 
sweep,  and  allowed  to  stay  open  for  two  hours  afterward. 
If  there  is  a  breeze,  so  much  the  better ;  it  blows  the  dust 
out,  especially  if  she  sweeps  in  the  direction  of  the  breeze. 
It  is  the  presence  of  dust  floating  in  the  air,  more  than  frag- 
ments of  trash  upon  the  floor,  that  makes  a  dirty  home. 


270  Healthful  Living 

When  the  carpet  is  swept,  dust  comes  from  the  carpet  it- 
self, especially  if  it  is  old.  Curtains  and  hangings  also  hold 
dust.  Hardwood  floors,  with  rugs  instead  of  carpets  are 
recommended,  and  oilcloth  and  linoleum  are  also  excellent 
substitutes  for  carpets.  Rugs  can  be  conveniently  cleaned 
at  any  time,  and  the  floor  can  be  cleansed  with  a  moist  cloth. 

Breathing  through  the  nose.  —  (1)  On  account  of  the  pro- 
jections of  the  turbinate*  bones  and  processes  into  each  nasal 
passage  and  the  roundabout  way  the  air  takes  in  passing 
through  the  nose  instead  of  the  mouth,  nasal  breathing  brings 
the  air  in  contact  with  a  much  larger  extent  of  moist  and 
warm  mucous  membrane  than  does  mouth  breathing.  The 
air  becomes  warm  and  does  not,  like  cold  air,  irritate  the 
trachea  and  bronchial  tubes.  (2)  The  air  becomes  purified, 
because  the  hairs  just  within  the  nostrils  and  the  mucous 
lining  of  the  latter  serve  to  catch  particles  of  dust. 
(3)  While  a  mouth  breather  is  eating,  sufficient  time  is  not 
taken  for  chewing  the  food,  but  it  is  swallowed  too  soon,  so 
urgent  is  the  necessity  for  breathing.  (4)  In  the  habitual 
mouth  breather,  the  nasal  mucous  membrane,  from  lack  of 
stimulus  of  the  cold  air,  dries  and  shrinks,  causing  discom- 
fort; and  since,  in  its  dry  condition,  the  circulation  easily 
becomes  obstructed,  there  is  a  predisposition  to  congestion 
and  catarrhal  nasal  affections  and  injury  to  hearing.  (5)  An 
unpleasant  expression  of  the  face  results  from  mouth  breath- 
ing (Fig.  78).  The  lower  jaw  recedes,  the  upper  teeth  pro- 
ject, the  nostrils  are  not  developed  and  in  a  grown  man  may 
be  no  larger  than  during  childhood.  (6)  A  person  has 
greater  endurance  in  muscular  exertion  if  he  breathes  strictly 
through  the  nose.  He  can  hold  out  much  longer,  his  lungs 
are  kept  more  expanded,  and  the  heart  is  not  oppressed ; 
and,  after  a  while,  a  "  second  wind  "  comes  to  him,  —  for 
instance,  during  running.  (7)  The  voice  has  more  reso- 
nance if  the  nasal  passages  are  open. 

A  Scotch  physician,  fully  appreciating  the  importance  of 


The  Respiration  27 1 

proper  breathing,  has  written  a  valuable  medical  paper, 
entitled,  "  Shut  Your  Mouth  and  Save  Your  Life."  Some- 
times the  cause  of  stopping  up  the  nose  in  children  is  en- 
largement through  growth  of  glandlike  structures  in  the 
upper  part  of  the  pharynx,  called  adenoids.  They  are  just 
behind  the  posterior  openings  of  the  nasal  passages,  and  can 
be  easily  removed  if  they  become  enlarged.  Persons  who 
sleep  with  the  mouth  open  are  likely  to  snore,  and  to  awake 
in  the  morning  with  the  mouth  and  throat  dry. 

Muscular  action  in  breathing.  —  Expand  your  lungs,  and 
see  whether  they  will  contract  of  themselves.  Contract 
your  lungs  and  see  whether  they  will  expand  of  themselves. 
See  whether  you  can  make  waist,  chest,  and  abdomen  ex- 
pand at  the  same  time.  You  learned  that  the  periods  of 
rest  taken  by  the  heart  muscles  amount  to  how  many  hours 
daily?  The  breathing  muscles  also  rest  a  considerable 
portion  of  the  time ;  with  calm  and  happy  people  they  rest 
more  than  with  people  of  anxious,  unquiet  dispositions.  We 
can  breathe  by  means  of  the  expiratory  muscles  alone  or  by 
means  of  the  inspiratory  muscles  alone,  or  by  using  each  set 
alternately.  When  all  the  breathing  muscles  are  relaxed, 
the  lungs  are  at  rest  in  what  may  be  called  the  neutral 
position,  since  there  is  neither  voluntary  contraction  nor 
expansion.  In  this  position  they  are  of  about  average  size. 
If  now  we  use  the  expiratory  muscles  and  contract  the  lungs, 
the  muscles  may  relax  during  inspiration  which  follows,  for 
it  will  be  accomplished  by  the  elasticity  of  the  abdominal 
walls  and  organs,  and  of  the  cartilages  of  the  thoracic  cage ; 
for  these  were  bent  when  the  cage  was  pulled  from  the 
neutral  position.  Try  this  method  of  breathing  for  a  few 
minutes. 

Or,  on  the  other  hand,  when  the  lungs  are  at  rest,  we  may 
breathe  by  using  the  inspiratory  muscles  (Fig.  160)  (dia- 
phragm and  intercostals) ,  thus  expanding  the  lungs  from  the 
neutral  position,  and  allowing  the  muscles  to  rest,  while  the 


272 


Healthful  Living 


\ 


FIG.  160. 


elasticity  of  the  parts  forces  out  the  air.     Try  breathing  in 

this  way. 

This  expanded  breathing  has  the  advantage,  over  con- 

tracted breathing,  of  removing  pressure  from  the  heart  and 

large  blood  vessels  in  the  chest,  and  allowing  the  heart  to 

work  with  greater  free- 
dom. It  also  keeps  the 
lungs  more  expanded. 
You  learned  in  another 
paragraph  that  it  is  the 
usual  method  of  quiet 
breathing  ;  but  strong, 
contracted  breathing 
sends  out  fouler  air  from 
deep  in  the  lungs  , 

In  both  of  these  ways 
of  using  the  breathing 
muscles,  there  is  a  pause 

Diagrams  illustrating  improper  and  •  ,t  npntrfll  nnsitirm 
proper  methods  of  breathing.  Dotted 

lines  show  area  of  expansion.  before   the  next   breath. 

FIG.  159.  —  Here,  owing  to  faulty  pos-     R    ,     •  f-  f  f 

ture,  expansion  of  chest  is  impeded  and 
breath   is   taken   by  the  "diaphragmatic     exertion,     as     when    run- 

ning,  Or  during  a  time  of 
excitement  and  in  some 

forrnc,    nf  illnpss    fhprp   is 
QeSS'  l 

no  pause  between  breaths, 
and  we  use  what  may  be  called  forced  breathing. 

Respiratory  exercises.  —  It  has  been  stated  that  strong 
contracted  breathing  sends  out  foul  air  from  deep  in  the 
lungs.  Some  people  argue  from  this  fact  that  we  can  re- 
move the  waste  material  by  deep  breathing,  and  some  even 
go  so  far  as  to  say  that  by  breathing  exercises  we  can  get 
strong  and  vigorous.  Now  our  physiology  must  help  us  at 
times  when  methods  of  getting  health  are  proposed.  It  is  known 
in  the  first  place  that  the  body  does  not  store  up  oxygen  in 


FIG.  159. 


Fm  160.  -Figure  properly  poised 
and  free  from  constriction.  Here  the 
entire  thorax  can  move  freely,  and  natural 
breathing  is  the  result. 


The  Respiration  273 

the  body  but  takes  in  oxygen  only  in  response  to  the  needs 
of  the  body.  If  one  stands  at  the  window  and  breathes  for 
15  minutes  will  more  oxygen  be  taken  into  the  body?  We 
have  learned  also  that  the  rate  and  depth  of  respiration  are 
governed  by  the  amount  of  carbon  dioxide  in  the  blood,  and 
when  this  gas  is  increased  the  respiration  is  increased  in 
order  to  remove  the  waste.  If  we  desire  the  effect  of  breath- 
ing exercises,  we  should  engage  in  some  game  or  activity 
that  will  make  us  breathe  much  faster.  In  this  way  our 
respirations  will  increase  without  our  thinking  about  them, 
and  in  addition  we  will  get  the  other  desirable  results  of  the 
activity. 

There  are  some  people  whose  chests  are  so  small  that  they 
are  unable  to  engage  in  any  vigorous  sport  because  their 
lungs  are  not  developed  enough  to  supply  the  required  oxy- 
gen. Such  persons  need  breathing  exercises  to  increase  the 
mobility*  of  the  chest  but  in  addition  they  need  forms  of 
activity  like  games,  also  running  in  the  case  of  boys,  and 
skipping  in  the  case  of  girls.  The  improper  ways  of  breath- 
ing that  are  seen  are  due  to  faulty  methods  of  dress,  and  if 
these  are  corrected  a  great  improvement  will  be  noticed. 

Abdominal  Breathing,  Chest  Breathing,  and  Natural 
Breathing.  —  It  should  be  remembered  that  breathing  is  a 
natural  process.  It  is  not  necessary  to  teach  animals  to 
breathe.  A  race  horse,  needing  a  very  efficient  respiratory 
mechanism,  breathes  without  being  taught.  The  breathing 
process  is  natural  in  man.  It  is  true  that  he  may  breathe 
with  difficulty  because  of  constricting  clothing  or  poor 
posture,  but  the  correction  of  the  conditions  causing  the  defect 
should  be  made  rather  than  an  attempt  to  teach  some  fancy 
method  of  breathing. 

There  has  been  much  discussion  among  physicians,  voice 
trainers,  and  elocutionists  as  to  the  proper  way  to  breathe, 
some  advocating  chest  breathing,  and  some  advocating  ab- 
dominal or  diaphragmatic  breathing  (Fig.  159).  The  fact 


274  Healthful  Living 

that  so  elementary  a  process  as  breathing  is  still  a  subject 
of  discussion  illustrates  how  imperfect  is  the  state  of  our 
physiological  knowledge,  especially  when  an  attempt  is 
made  to  apply  it  to  practical  purposes.  The  author  believes 
that  pure  chest  breathing  and  diaphragmatic  breathing  are 
both  wrong,  and  that  what  may  be  termed  natural  breath- 
ing is  the  method  to  teach  when  corrections  are  to  be  made 
(Fig.  160). 

Natural  breathing  employs  movement  of  both  chest  and 
diaphragm,  the  greatest  expansion  being  in  neither  chest  nor 

abdomen,  but  at  the  waist  (Fig. 

*yVYv/v^A/l/)/l/1  (\      161)?  and  diminishing  in  amount 
Men  both    upward     and     downward. 

/T/y*|/|/"jyVvx^N^y^^^     The    objection    to     pure    chest 
Woman  fn  Corset  breathing    is    that    the    marked 

movement  of  the  upper  part  of 
the  bony  cage  requires  exhaust- 
ing effort;    such  movement  can 
'Man  m  Corset  be   employed   without  waste   of 

strength  for  only  a  short  period, 
as  in  gasping  for  breath  or  during 
great  muscular  exertion. 

In  natural  breathing,  the  dia- 


F.O.  161. -Breathing  trac-    phragm  contracts  but  at  the  same 
ings  (Kellogg) .   Motion  of  chest    time  the  ribs  are  lifted  upward 

recorded  at  left  and  of  waist  at  j   outward     flnrl    tV»p   nnint«;   of 

right.     Interpret  these  tracings     anCl   outwaro->    and    tne   Pomts   ot 

by  what  is  shown  in  Fig.  160.      attachment    of    the    diaphragm 

are  thus  raised  and  separated  so 

that  the  diaphragm  flattens  without  any  great  descent. 
But  in  pure  abdominal  breathing,  the  movement  is  con- 
fined to  the  diaphragm  and  abdomen,  and  lateral  action 
of  the  chest  is  suppressed  (Fig.  159).  The  effect  of  this 
is  to  cause  too  great  a  displacement  downward  of  the 
liver,  stomach,  kidneys,  colon,  and  other  organs.  But  in 
natural  breathing,  any  great  degree  of  downward  movement 


The  Respiration  275 

is  prevented  by  expansion  of  the  trunk  at  the  waist.  In 
abdominal  breathing,  the  abdominal  walls  are  entirely  re- 
laxed as  the  diaphragm  descends,  and  the  liver  and  other 
organs  are  moved  but  not  compressed.  In  natural  breath- 
ing they  are  compressed  and  slightly  moved,  and  the  com- 
pression squeezes  the  blood  out  of  them  toward  the  heart 
and  presses  the  lymph  upward,  through  the  thoracic  duct ; 
the  expansion  of  the  chest  at  the  same  time  helps  to  draw 
the  blood  upward.  During  expiration  fresh  blood  is  sent 
back  to  the  abdominal  organs,  and  so  they  are  kept  fresh 
and  strong.  Women  who  wear  skirts  with  bands  tight  enough 
to  support  them  at  the  waist,  gradually  lose  the  power  of 
lifting  the  ribs  outward  at  the  waist.  This  expansion  is 
most  important  for  good  breathing,  because  the  lungs  are 
largest  there.  The  belt  used  by  men  for  supporting  the 
trousers,  should  rest  on  the  hip  bones  (ilium)  and  not  above 
them. 

Ventilation*  —  The  evil  effects  of  rebreathirig  air  can 
hardly  be  exaggerated.  The  blood  stagnates,  the  heart  acts 
slowly,  the  brain  is  clogged,  the  head  aches,  and  either  a  dull 
or  a  feverish  feeling  arises.  The  body  becomes  sensitive  to 
cold.  The  skin  becomes  pale,  the  blood  is  loaded  with  im- 
purities, and  the  whole  body  is  obstructed  with  refuse  ma- 
terial. In  such  a  human  body,  colds,  catarrh,  consumption, 
and  other  diseases  readily  develop.  The  constant  breathing 
of  even  the  slightly  impure  air  of  most  private  houses  can- 
not but  tend  to  undermine  the  health  and  prevent  that 
perfect  soundness  of  body  which  thorough  ventilation  or  life 
in  the  open  air  insures. 

Judgment  with  regard  to  ventilation  is  rare.  In  many 
churches  and  assembly  rooms  the  windows  are  tightly  closed 
except  in  warm  weather.  If,  during  the  meeting,  the  room 
becomes  too  warm,  some  one  will  open  one  or  more  windows 
to  their  full  height ;  the  strong  draught  soon  cools  the  room 
and  chills  some  one,  whereupon  he  goes  to  the  window  and 


276  Healthful  Living 

shuts  it  tight.  One  absurd  extreme  thus  follows  another. 
All  that  was  necessary,  if  there  was  no  scientific  provision 
for  ventilation,  was  for  all  of  the  windows  to  have  been 
opened,  for  an  inch  or  less,  when  the  assembly  began,  and 
allowed  to  remain  so ;  then  no  one  would  have  been  too  hot 
or  too  cold,  or  would  have  suffered  from  vitiated*  air. 

The  ventilation  of  the  schoolroom  is  often  deplorable. 
A  visitor,  upon  entering  a  schoolroom,  especially  if  the 
school  has  been  in  session  for  an  hour  or  more,  may  notice 
a  stifling,  foul-smelling  atmosphere.  The  children  have 
rushed  in  from  their  active  games  with  their  clothing  satu- 
rated with  perspiration.  Their  healthy  skins  perspire  more 
freely  than  do  those  of  adults.  Some  of  them  may  have 
coughs  or  colds,  some  may  have  come  from  sick  rooms.  The 
dust  from  the  pattering  of  many  feet,  the  clouds  of  chalk 
dust,  accumulate  until  they  become  almost  unbearable,  and 
all  that  gets  out  leaves  the  room  on  the  clothes  of  the  pupils, 
or  on  the  mucous  membrane  of  their  nasal  passages  and 
lungs ;  for  the  janitor  is  more  ignorant  usually  than  the 
housekeeper,  and  unless  forced  to  do  so  he  will  not  open 
the  windows  before  sweeping  because  of  the  trouble;  or, 
if  persuaded  to  open  them,  he  must  be  compelled  by  the 
principal  to  allow  them  to  remain  open  for  the  dust  to  blow 
out,  otherwise  he  will  close  them  on  leaving  each  room  to 
avoid  the  annoyance  of  returning. 

These  are  the  conditions  of  many,  many  schoolrooms  and 
homes,  for,  unfortunately,  some  persons'  knowledge  of  physi- 
ology is  never  put  into  practice.  It  is  not  strange  that 
lung  troubles  are  common  and  that  people,  ignorant  of  their 
cause,  take  "  patent  medicines  "  instead  of  pure  air.  Many 
of  the  Indians  of  Patagonia  died  of  consumption  within  nine 
months  after  being  taught  by  the  missionaries  to  live  in 
houses.  The  missionaries  neglected  to  tell  them  how  to  live 
in  houses. 

It  is  necessary  to  give  children  knowledge  of  the  geography 


The  Respiration 


277 


of  Africa  and  other  remote  lands,  but  it  is  at  least  as  neces- 
sary to  train  them  to  sit  and  to  stand  correctly.  Frequent 
periods  of  relaxation  and  play  would  help  to  counteract  the 
deforming  effects  of  prolonged  sitting,  would  help  them  to 
grow  up  well-formed  men  and  women,  and  would  make 
them  more  ready  to  learn  the  geography  as  well. 

The  health  of  children  at  school  often  suffers,  and  parents 
usually  think  it  is  because  of  the  number  of  studies.     This 


FIG.  162.  —  The  proper  method  of  ventilating  a  room  with  stove.  The 
stove  is  on  the  side  toward  the  cold  winds.  The  inlet  is  near  the  stove, 
the  outlet  farther  away.  If  the  window  near  the  stove  were  lowered  from 
the  top,  what  would  happen?  If  another  window  near  the  stove  were 
opened,  what  might  happen?  If  the  prevailing  cold  winds  came  from  the 
opposite  direction,  what  changes  should  be  made  in  the  room?  How 
do  you  ascertain  whether  the  outlet  fails  to  serve  its  purpose  and  become 
an  inlet? 

idea  is  no  doubt  largely  erroneous.  The  breathing  of  the 
bad  air,  both  at  home  and  at  school,  the  close  confinement 
in  the  schoolroom,  sitting  in  a  cramped  position,  and  study- 
ing by  improper  light,  are  the  true  causes  in  a  majority  of 
cases. 

Some  persons  in  their  anxiety  for  pure  air  become  ex- 
tremists, and  forget  that  the  body  may  likewise  be  injured 
by  cold.  In  ventilating  a  room,  not  one  but  two  purposes 
must  be  kept  in  view :  to  furnish  air  that  is  pure,  and  air 
at  the  proper  temperature. 


278 


Healthful  Living 


Methods  of  ventilation  depend  upon  the  principle  that 
hot  air  is  lighter  than  cold  air  and  is  pushed  up  by  it.  If 
you  have  two  openings  for  ventilation,  one  higher  than  the 
other,  at  which  opening  does  the  warm  air  go  out?  If  the 
higher  opening  is  near  the  ceiling,  do  the  persons  in  the  room 
get  the  coldest  or  warmest  air?  Does  such  a  method  econo- 
mize the  fuel  ?  If  the  inlet  is  near  the  floor,  why  should  the 
stove  be  near  the  inlet?  Why  should 
the  outlet  be  on  the  side  of  the  room  far- 
thest from  the  stove  ? 

Good  ventilation  is  arranged  so  that 
the  fresh  air  shall  be  heated  before  or 
just  after  it  enters  the  room,  and  that  it 
shall  pass  across  the  room  in  order  that 
the  inmates  may  get  the  benefit  of  both 
its  warmth  and  its  purity  before  it  passes 
out  (Figs.  162,  164).  Test  the  direction 
of  the  air  currents  in  your  bedroom  and 
in  your  schoolroom  by  means  of  a  spider 
web  hanging  from  the  end  of  a  stick. 
Why  is  it  best  not  to  have  the  outlet  on 
the  side  of  the  house  toward  the  pre- 

vailins  wind  in  winter?  If  the  inlet  is 

so  situated  that  the  cold  air  does  not 
pass  over  the  stove,  a  board  or  screen 
may  be  placed  before  the  window  to  deflect  the  current  up- 
ward and  prevent  its  chilling  those  seated  nearest  the  window 
(Fig.  163).  If  you  find  by  holding  your  hand  near  the  inlet 
that  there  is  a  good  inward  current,  you  may  be  sure  there 
is  sufficient  outlet  ;  although  if  it  is  not  far  enough  from  the 
stove,  heat  will  be  wasted.  If  you  know  there  is  a  strong 
outward  current,  for  instance  when  a  fire  is  burning  in  an 
open  fireplace,  you  may  be  sure  that  the  same  amount  of  air 
is  entering  somewhere,  if  only  through  minute  cracks. 
When  over-enthusiastic  people  become  interested  in  ven- 


FIG.  163.—  Window 
board  prevents  cold  air 


is  directed  upward. 


The  Respiration 


279 


tilation,  they  sometimes  injure  themselves  by  chilling 
draughts  and  low  temperatures.  The  temperature  of  the 
room  should  be  kept  between  65  and  68  degrees  F.  The  fore- 
going directions  for  ventilation  apply  to  cold  weather.  For 
warm  weather  no  special  directions  are  necessary,  for  most 
people  are  more  anxious  to  avoid  unpleasant  heat  or  the 
possibility  of  soiling  their  collars  with 
perspiration,  than  they  are  moved 
by  the  danger  of  breathing  foul  air. 

The  effect  of  tobacco  on  the  respira- 
tory organs.  —  The  hot  smoke  irri- 
tates and  dries  the  mucous  membrane 
of  the  mouth  and  throat,  producing 
an  unnatural  thirst  that  may  readily 
lead  to  the  use  of  alcoholic  drinks. 
Inhaling  the  poisonous  smoke,  which 
occurs  to  the  greatest  degree  in 
cigarette  smoking,  inflames  the  deli- 
cate mucous  lining  of  the  bronchial 
tubes  and  air  cells.  There  may 
result  from  this  an  irritating  cough, 
short  breath,  and  chronic  bronchial 
catarrh. 


FIG.  164.  —  Stove  for 
rural  school  where  furnace 
is  not  used.  The  air  en- 
ters through  a  special  inlet 

General  considerations.  —  The  hy-  and  is  warmed  as  it  passes 
giene  of  respiration  is  only  a  phase  throush  a  hood  surround- 

»    ,,        ,  .    ,.    .  ing  the  stove. 

of  the  hygiene   of  living.      All   the 

methods  that  are  available  to  help  people  to  live  finer  individual 
lives  and  to  preserve  their  strength  and  health  for  the  welfare  of 
the  race  are  valuable.  Cleanliness  of  air  is  very  important, 
but  cleanliness  of  living  is  more  important. 

Cleanliness.  —  Nearly  all  people  are  very  careful  to  wear 
clothes  that  are  perfectly  neat  and  clean.  Dust  or  mud  upon 
their  clothes  is  considered  the  highest  degree  of  uncleanli- 
ness.  Many  think  it  of  the  highest  importance  to  health 
and  refinement  to  keep  the  skin  clean  by  regular  baths. 


280  Healthful  Living 

But  there  are  a  few  that  think  it  of  still  greater  importance 
to  keep  the  air  clean  that  goes  into  the  lungs.  A  few  also 
think  it  necessary  to  keep  the  alimentary  canal  pure  through- 
out by  reasonable  eating  and  living.  We  also  meet  with 
those  who  believe  not  only  that  the  clothes,  the  skin,  the 
lungs,  the  digestive  organs,  must  be  kept  clean,  but  that  the 
blood  must  be  clean  and  fresh,  ever  renewed  by  a  strong  and 
vigorous  flow,  and  they  so  live  that  as  far  as  possible  it  shall 
always  be  so.  The  daintily  dressed  lady  or  the  dandified 
man  would  be  horrified  at  a  particle  of  mud  that  fell  upon 
the  clothes,  but  sometimes  if  you  are  so  unfortunate  as  to 
catch  a  whiff  of  the  breath  of  such  a  person,  its  repulsive, 
sickening  odor  shows  that  foulness  and  uncleanliness  have 
taken  possession  of  the  lungs,  or  digestion,  or  blood.  We 
should  be  careful  to  observe  these  five  degrees  of  cleanliness, 
but  which  should  we  value  most  highly?  There  is  another 
aspect  of  cleanliness  that  relates  to  the  way  the  person  lives. 
It  is  concerned  with  thoughts  and  actions.  What  is  the 
relative  value  of  these  three  :  clean  clothes,  clean  body,  and 
clean  conscience? 

The  Mistake  of  the  Over-studious.  —  The  pale  student, 
thinking  only  of  the  desire  for  learning  aroused  by  teacher 
or  parents,  and  neglecting  the  promptings  of  his  natural 
instincts*  toward  complete  living,  thinks  he  is  doing  wisely 
and  right  when  he  is  constantly  delving  into  books.  On 
the  contrary,  he  is  sinning  against  part  of  his  nature  and 
unfitting  himself  for  accomplishing  the  best  work  he  is 
capable  of  doing. 

The  Essential  Unity  of  Body  and  Mind.  —  All  students 
should  remember  the  fact  that  the  individual,  particularly  as 
regards  mind  and  body,  is  a  unit  and  the  health  of  the  whole 
is  dependent  upon  the  health  and  vigor  of  its  parts.  The 
mind  cannot  achieve  extraordinary  success  at  the  expense 
of  the  body,  without  a  loss  of  real  health  values  in  both  mind 
and  body.  Furthermore,  it  is  important  to  remember  that 


The  Respiration  281 

the  brain,  in  its  development  from  lower  forms,  followed 
the  development  of  the  muscular  system,  and  for  this  reason 
we  must  always  look  to  the  muscular  system  as  the  founda- 
tion upon  which  to  build  a  safe  and  serene  mind.  This 
does  not  mean  that  one  should  seek  to  develop  large  and 
unsightly  muscles  with  the  hope  of  thereby  achieving  mental 
power,  but  it  does  mean  that  bodily  activity  in  physical  forms 
is.  absolutely  essential  for  the  highest  and  finest  development 
of  the  brain  and  nervous  system.  The  student  in  school  or 
college  who  seeks  to  be  excused  from  physical  education 
classes  is  progressing  in  a  direction  which  will  bring  a  weak 
and  devitalized  body  unless  he  provides  on  the  outside  a 
large  and  wholesome  participation  in  games  or  sports.  In 
this  day  of  interest  in  and  plans  for  national  preparedness, 
it  is  the  duty  of  the  boys  and  girls  of  the  nation  to  share 
in  this  movement  and  bring  to  the  service  of  the  nation 
in  all  fields  of  endeavor  a  finer  body  and  a  more  vigorous 
spirit. 

APPLIED   PHYSIOLOGY 

Exercise  I 

1.  State  how  in  the  case  of  a  person  of  poor  figure,  a  gradual 
remolding  of  the  cartilages,  the  strengthening  of  the  muscles,  and 
the  practice  of  chest  lifting  may  each  contribute  toward  acquiring 
a  correct  and  perfect  figure. 

2.  How  far  is  it  in  one's  power  to  determine  the  shape  and 
appearance  of  his  own  body? 

3.  Give  reasons  why  the  weight  of  our  clothing  should  hang 
from  the  shoulders  and  not  from  the  waist. 

4.  How  can  the  hat  be  ventilated?     (A  punch  for  making 
the  hole  costs  a  dime.) 

5.  Name  habits  that  impair  the  power  of  the  lungs. 

6.  How  could  you  convince  a  person  that  a  bedroom  should  be 
open  while  and  after  it  is  swept?     That  it  should  be  ventilated 
at  night? 

7.  Why  do  some  persons  "  get  out  of  breath  "  readily  after  a 
meal? 


282  Healthful  Living 

8.  Can  a  person  become  so  used  to  bad  air  that  he  will  not 
notice  it  ?     That  it  will  not  injure  him  ? 

Exercise  II 

9.  Which   is   the   more   offensive,    the   tobacco   chewer,    who 
chiefly  pollutes  the  ground,  or  the  smoker,  who  pollutes  the  air? 

10.  Why  are  those  who  have  pimples  on  the  face  likely  to 
multiply  their  number  by  picking  and  squeezing  them  with  the 
fingers? 

11.  Give  the  advantages  of  slow,  deep  breathing  as  compared 
with  quick,  shallow  breathing. 

12.  Why  do  those  who  stand  up  to  hoe  not  get  tired  half  as 
quickly  as  those  who  bend  or  "  hump  "  over? 

13.  Why  do  students  who  sit  in  rocking-chairs,  or  from  other 
causes  lean  the  head  forward  when  they  study,  often  find  that 
they  recover  from  drowsiness  if  they  sit  erect? 

14.  How  are  high  collars  a  fruitful  source  of  bad  colds? 

15.  Is  ventilation  easier  in  winter  or  in  summer? 

16.  If  the  draught  up  the  chimney  of  the  fireplace,  when  the 
fire  is  burning,  takes  up  a  volume  of  air  sufficient  for  many  people, 
why  is  it  unwise  to  open  a  window? 

LABORATORY   EXERCISES 

Experiment  1.    To  study  modifications  of  the  breath. 

Study  the  following  list  of  experiments  with  your  own  breath- 
ing. Write  after  each  word  I  or  E  according  as  inspiration  or 
expiration  is  chiefly  involved  in  the  action  : 

Sighing  Coughing  Sneezing 

Sobbing  Laughing  Hiccoughing 

Crying  Yawning  Snoring 

Experiment  2.    To  study  the  mechanism  of  respiration. 

Material.  —  Respiration  apparatus  as  show  in  Figure  165. 

Method  and  observation.  —  (a)  Locate  upon  the  respiration 
scheme  what  corresponds  to  the  following  structures :  1  trachea. 
2  glottis,  3  thoracic  cavity,  4  lungs,  5  intrapleural  space,  6  dia- 
phragm. (6)  Produce  inspiration  by  lowering  the  diaphragm. 
What  happens  to  the  lungs?  What  change  occurs  in  the  pressures 
in  the  chest  cavity?  (c)  Produce  expiration  by  raising  the  dia- 
phragm. Describe  and  explain  what  is  noticed,  (d)  Close  the 
glottis  and  try  experiments  a,  6,  and  c. 


The  Respiration 


Experiment  3.  To  study  the  effect  of 
forced  breathing. 

Material.  —  Watch  with  second 
hand. 

Method  and  observation.  —  The  sub- 
ject, seated,  breathes  naturally  and 
counts  the  rate.  Then  breathes  as 
deeply  as  possible  about  18  times  a 
minute.  The  attention  should  be 
fixed  on  drawing  deep  inspirations. 
Continue  it  for  30  seconds,  at  once 
at  the  end  of  the  30  seconds  count  the 
rate  and  compare  this  with  the  rate 
before  the  experiment. 

The  deep  inspirations  removed  the 
excess  of  carbon  dioxide  from  the  blood, 
and  with  this  removed  the  stimulus 
was  less  to  the  respiratory  center  in 
the  medulla  and  so  the  rate  was 
slowed. 

Repeat  the  experiment  for  one 
minute. 

Experiment  4.  To  study  forced  breath- 
ing without  the  excessive  elimina- 
tion of  carbon  dioxide. 

Repeat  experiment  3  while  holding 
a  paper  bag  over  the  nose  and  mouth 
of  the  subject.  Record  the  results  ob- 
tained, compare  with  experiment  3  and 
explain. 

Experiment  5.  To  study  the  produc- 
tion of  apnea  (period  of  no  respi- 
ration). 

(a)  At  the  end  of  a  normal  expi- 
ration, the  subject  holds  the  breath 
until  no  longer  able  to  do  so.  How 
long  can  it  be  held? 

(6)  Repeat  experiment  (a)  after 
taking  a  deep  inspiration  and  counting 
from  the  end  of  a  normal  expiration. 
How  long  can  it  be  held  ?  Is  this  period 
longer  or  shorter  ?  Why  is  this  so  ? 


FIG.  165.  —  This  apparatus 
is  made  by  -tying  over  the 
bottom  of  the  bell  jar  a  sheet 
of  dental  dam  which  has  tied 
in  the  center  a  marble  for  a 
handle.  The  mouth  is  fitted 
with  a  cork  through  which 
passes  a  glass  tube  with  stop 
cock.  At  one  end  of  the  glass 
tube  is  tied  a  small  rubber 
bag.  When  the  tube  is  in- 
serted in  the  jar  and  the  cork 
put  in  place  the  rubber  dia- 
phragm should  be  pressed  up- 
ward as  it  is  iri  the  human 
body. 


284 


Healthful  Living 


Experiment  6.  Respiration  may  be 
studied  by  means  of  the  appa- 
ratus shown  in  Figure  166  ob- 
tained from  the  Harvard  Appa- 
ratus Company,  Back  Bay  Post 
Office,  Boston,  Massachusetts. 


GLOSSARY 

Atmosphere.  —  The  gaseous  mass, 
chiefly  air,  that  surrounds  the 
earth.  This  mass*  at  sea  level 
will  support  a  column  of  mer- 
cury 30  inches  high  at  a  tempera- 
ture of  0°  C.  This  pressure  is 
sometimes  stated  as  being  equal 
to  15  pounds  to  the  square 
inch. 

Humidity.  —  Refers  to  the  moisture 
in  the  atmosphere.     This  mois- 
ture varies  and  two  terms  are 
used  to  express  the  relation  as 
it  exists  at  different  times. 
Absolute  humidity.  —  The  amount 
of  water  vapor  in  the  air  ex- 
pressed   in    the    number    of 
grains  of  moisture  per  cubic 
foot  of  air. 

Relative  humidity.  —  The  ratio  of 
the  actual  quantity  of  mois- 
ture in  the  air  to  the  quan- 
tity that  would  saturate  it  at 
the  temperature  and  pressure 
of  the  air  at  that  time. 

Insertion.  —  The  point  or  points  of  attachment  of  a  muscle 
to  a  bone.  The  insertion,  as  contrasted  with  the  origin, 
the  other  attachment,  is  considered  as  more  movable. 
Another  distinction  between  insertion  and  origin  is  .that 
the  latter  is  on  the  bone  nearer  the  center  of  the  body, 
and  the  insertion  further  from  the  central  part  of  the 
body. 


FIG.  166.  —  The  respiration 
scheme.  About  one  third  the 
actual  size.  (Harvard  Appa- 
ratus Co.,  Boston.)  The  water 
diaphragm  is  made  to  move  up 
and  down  and  causes  a  filling  of 
the  rubber  bag.  The  water  is 
moved  by  means  of  water  in 
connection  with  the  tube  at  the 
bottom  of  the  picture.  The 
left-hand  mercury  U-tube  shows 
the  change  of  pressure  within 
the  interpleural  space  ;  the  other 
U-tube  shows  the  change  in 
pressure  within  the  lung. 


The  Respiration  285 

Instinct.  —  A  natural,  spontaneous  impulse  moving  to  action  with- 
out the  intervention  of  reason.  This  impulse  acts  most 
powerfully  in  connection  with  preservation  and  development. 

Mobility.  —  The  quality  of  being  freely  movable. 

Negative  pressure.  —  The  pressure  of  the  atmosphere  in  millimeters 
of  mercury  is  760.  A  pressure  less  than  760  mm.  of  mercury 
is  a  negative  pressure. 

Origin.  —  One  of  the  points  of  attachment  of  a  muscle  to  a  bone. 
It  is  attached  at  the  more  stationary  part  of  the  bone  or  is 
nearer  the  central  part  of  the  body. 

Statistics.  —  A  mass  of  facts  pertaining  to  a  body  of  things,  system- 
atically gathered,  classified,  and  tabulated.  Statistics  are 
essential  in  the  conduct  of  a  large  business,  in  manufacturing 
and  in  all  scientific  studies. 

Temperature.  —  The  condition  of  the  body  or  thing  as  regards 
heat  and  cold. 

Turbinate.  —  Top-shaped.  The  turbinate  bones  of  the  nose  are 
of  this  shape. 

Ventilation.  —  The  process  of  providing  free  circulation  of  air. 

Vitiated.  —  Refers  to  air.  To  vitiate  is  to  injure  the  qualities. 
Vitiated  air  is  air  that  has  lost  the  qualities  of  freshness,  of 
freedom  from  dust  and  bacteria,  and  is  not  of  the  proper  tem- 
perature and  moisture. 


CHAPTER  XV 
THE  NERVOUS  SYSTEM 

I.    The  Functions  of  the  Nervous  System. 
Communication 
Coordination 

II.   The  Nerve  Cell  the  Unit  of  the  Nervous  System. 
Dendrites 
Axone 
Neuron 
Ganglion 
Nerve  center 
Neuroglia 

Terminations  of  nerve  fibers 
Efferent,  afferent,  and  association  fibers 

III.  Nerve  Action. 

IV.  Sensations. 

General 
Special 

V.    Injury  to  Nerves. 

VI.    General  Arrangement  of  the  Nervous  System. 
The  spinal  cord 
The  autonomic  system 
The  brain 


The  functions  of  the  nervous  system.  Communication.  — 
The  amoeba  and  other  one-celled  animals  need  no  nervous 
system,  but  the  larger  animals,  consisting  of  a  colony  of 
cells,  as  it  were,  need  a  means  of  communication  between 
the  cells,  in  order  that  their  life  may  be  harmonious.  On 
Robinson  Crusoe's  island  a  telephone  or  a  post  office  system 
would  have  been  of  no  use,  but  a  number  of  individuals 
living  together  and  practicing  a  division  of  the  labor  of  the 

286 


The  Nervous  System  287 

community  for  their  mutual  advantage,  are  compelled  to 
communicate  with  each  other  in  order  to  make  their  wants 
known.  The  lowest  of  the  many-celled  animals,  such  as  the 
sponges,  have  no  cells  specially  set  apart  for  carrying  messages 
between  the  cells,  but  each  cell  passes  the  impulses  it  re- 
ceives to  its  neighbor  cell.  This  will  do  for  a  small  and 
simple  community  of  cells,  but  a  larger  community,  like 
one  of  the  higher  animals,  possesses  certain  cells,  called  nerve 
cells,  whose  chief  function  is  to  keep  up  the  communication 
between  the  cells.  In  the  chapter  on  nerve  tissue  you  learned 
that  the  nerve  cells  did  this  by  means  of  branches,  which  in 
some  cases  are  several  feet  long. 

Coordination.  —  Did  you  ever  see  a  crowd  of  people  at  a 
fire  when  a  neighbor's  house  was  burning?  Everybody 
ran  out,  yet  very  little  was  done.  Everybody  shouted 
orders  which  nobody  obeyed.  But  on  the  arrival  of  the 
chief  of  the  fire  department  or  the  head  of  a  fire  company, 
who  had  had  experience  in  the  control  of  men  fighting  a  fire, 
the  scene  changed ;  valuable  property  was  saved,  and  the 
fire  was  stopped. 

Every  community  has  certain  deliberative  and  controlling 
bodies ;  these  may  be  a  board  of  aldermen,  a  court  of  jus- 
tice, a  legislature,  or  a  congress.  In  a  similar  way  the  great 
number  of  individual  cells  which  make  up  the  human  body 
must  be  controlled  by  some  central  power,  or  they  will  not 
work  in  harmony;  nothing  will  be  accomplished,  but  a 
state  of  anarchy  and  helplessness  called  disease  will  follow. 
The  seat  of  this  central  controlling  power  is  located  in  the 
brain. 

The  nerve  cells  receive,  modify,  and  send  out  impulses. 
By  these  three  kinds  of  acts  the  nervous  system  accomplishes 
what  is  called  coordination.  This  term  signifies  not  only 
that  the  cells  work  together  at  the  same  time,  but  that  they 
work  together  as  a  part  of  a  plan  for  the  accomplishment 
of  some  definite  result.  Suppose  that  a  man  sees  a  bright 


288  Healthful  Living 

dollar  on  the  road  and  picks  it  up.  In  order  that  he  may 
do  this,  the  cells  receiving  through  the  optic  nerve  the  im- 
pression of  the  shining  coin  must  be  in  communication, 
either  directly  or  indirectly,  with  the  muscles  of  the  hand ; 
and  that  the  hand  may  reach  the  coin,  the  muscles  of  the 
arms,  legs,  trunk,  head,  and  neck  must  act  together.  Even 
the  heart  and  respiratory  muscles  must  modify  their  action 
somewhat  to  suit  the  movement. 

Other  Organs  besides  Muscles  Must  Be  Coordinated.  — 
Suppose  a  boy  sees  a  large  red  apple.  He  notices  the  odor 
which  tells  him  it  is  ripe,  and  his  "  mouth  waters  "  for  it ; 
that  is,  the  salivary  glands  begin  to  work,  even  before  he 
puts  the  apple  to  his  mouth.  The  chewing  and  swallowing, 
the  secretion  and  peristalsis  in  the  digestive  organs,  are  all 
carried  on  under  the  control  of  impulses  that  reach  them 
through  the  nerves.  Without  these  impulses,  the  salivary 
glands  would  not  work  when  the  mouth  was  chewing  the 
food ;  the  dry  food  would  stick  to  the  esophagus  and  have 
to  be  washed  down  with  water ;  the  gastric  juice  would  not 
be  secreted  at  just  the  right  time ;  the  food  would  ferment 
in  the  stomach,  and  the  person  would  soon  be  ill. 

The  nerve  cell  the  unit  of  the  nervous  system.  —  You 
learned  when  studying  the  tissues  that  the  nervous  system 
consists  of  nerve  cells  with  their  branches,  called  nerve  fibers. 
Nerve  cells  are  microscopic  bits  of  protoplasm,  like  other 
cells,  yet  they  are  remarkable  among  animal  cells  for  their 
large  size.  Some  of  the  cell  bodies  in  the  spinal  cord  are  so 
large  as  to  be  almost  visible  to  the  unaided  eye,  and  they 
have  branches  leading  from  the  cord  to  the  hand  or  foot. 
Each  cell  contains  a  nucleus,  within  which  is  a  nucleolus 
(Fig.  167).  Nerve  cells  are  the  most  remarkable  in  the  body 
for  irregularity  of  shape  (Fig.  176) ;  some  of  them  have  so 
many  branches  that  they  have  a  starlike  appearance. 

Dendrites*  —  The  dendrites  are  branches  of  nerve  tissue 
from  the  cell  body.  The  dendrites  of  a  nerve  cell  are  the 


The  Nervous  System 


289 


treelike  branches  which  bring  impulses  to  the  cell  (Fig.  31). 
Through  the  dendrites  the  cell  may  be  in  communication 
with  numerous  other  cells.  A  branch  of  one  cell  does  not 
join  the  branch  of  another  cell.  It  has  not  yet  "been  settled 
by  physiologists  whether  the  ends  of  the  dendrites  of  com- 
municating cells  actually  touch. 

The  axone  and  its  parts.  —  In  most  of  the  fully  developed 
nerve  cells,  one  of  the  branches  is  very  greatly  prolonged 
as  a  fine  thread  of  protoplasm,  which  becomes  the  core  of  a 
nerve  fiber  (Fig.  167).  Every  nerve  fiber  has  such  a  core. 


Axis  Cyftnde. 

Afettuttery  Sheath 


WucJeus 
-JVeuroyJfa  Cell 


FIG.  167.  —  Nerve  cell  showing  axone,  medullary  sheath,  and  field 
of  fibers. 

In  most  of  them  this  central  thread  of  protoplasm  becomes 
covered  with  two  coats  (Fig.  32) ;  an  outside  protective  coat 
forms  a  tube,  called  the  connective  sheath,  and  between  the 
walls  of  this  tube  and  the  central  thread  is  a  coat  of  semi- 
liquid,  fatty  substance  called  the  medullary  sheath,  which, 
shining  through  this  outer  sheath,  gives  a  silvery  white  ap- 
pearance to  the  fiber.  Such  fibers  are  called  medullated* 
fibers,  or  white  fibers.  Some  fibers  lack  the  medullary 
sheath,  and  are  called  non-medullated,  or  gray  fibers. 

Neuron*  —  One  nerve  cell  together  with  all  its  branches, 
both  dendrites  and  axone,  is  called  a  neuron.  A  neuron  is 
the  unit,  and  the  nervous  system  is  built  up  of  an  enormous 


290 


Healthful  Living 


number   of   these   units,    together   with   supporting   tissue 
(Fig.  167). 

Many  nerve  fibers  may  be  bound  together  by  connective 
tissue  until  they  form  a  cord  large  enough  to  be  seen  by  the 
unaided  eye  (Fig.  168).  A  bundle  of  nerve  fibers  is  called 
a  nerve.  The  sciatic  nerve  in  the  thigh  is  as  large  as  the 
end  of  the  little  finger.  The  fatty  sheaths  of  the  fibers  are 
supposed  to  insulate  the  fibers  so  that 
a  nerve  impulse  cannot  go  across  to 
another  fiber ;  they  serve  the  same  pur- 
pose as -the  insulating  substances  with 
which  wires  used  to  conduct  electricity 
are  sometimes  coated.  As  a  rule,  a 
large  nerve  accompanies  an  artery  down 
the  inside  of  each  limb,  and  across  the 
joint  on  the  side  toward  which  the  limb 
bends.  Thus  they  are  well  protected. 
One  exception  to  this  is  a  nerve  cord 
which  crosses  the  elbow  on  the  side 
away  from  which  the  elbow  bends. 
Therefore,  it  is  sometimes  hit,  and  the 
end  of  the  bone  there  is  called  the  funny 
bone  because  of  the  tingling  sometimes 
felt,  as  if  it  were  in  the  hand  at  the 
termination  of  the  nerve. 

Ganglion.  —  The  cells  are  not  scat- 
tered singly  throughout  the  nervous 
system  but  are  gathered  into  groups.  This  seems  to  afford 
easier  communication  from  one  cell  to  another  through  their 
branched  dendrites,  which  are  unusually  short.  One  such 
group  of  cells  situated  outside  the  cord  is  called  a  ganglion. 
Ganglion  is  not  to  be  confused  with  the  term  "  nerve 
center,"  which  relates  primarily  to  function.  The  term 
ganglion  refers  to  structure. 

Nerve  center.  — PL  group  of  nerve  cells,  situated  in  the 


FIG.  168. —  Section 
of  two  nerves,  show- 
ing many  nerve  fibers 
bound  together  in  con- 
nective tissue  sheaths, 
to  make  nerves. 


The  Nervous  System  291 

brain  or  spinal  cord,  performing  a  definite  function,  such  as 
controlling  the  muscles  of  breathing,  form  what  is  called  a 
nerve  center.  The  brain  consists  of  a  number  of  large  nerve 
centers  with  their  connecting  fibers.  There  are  many  nerve 
centers  in  the  spinal  cord  also.  Where  nerve  cells,  ganglia 
and  gray  fibers  are  abundant,  the  nerve  substance  is 
gray ;  where  medullated  fibers  with  their  hidden  gray  cores 
are  abundant,  the  nerve  substance  is  white  in  appearance. 
This  led  anatomists  and  physiologists  in  times  past  to  classify 
nerve  substance  as  gray  matter  and  white  matter. 

Neuroglia.  —  The  fibers  and  cells  of  both  the  gray  and  the 
white  matter  are  held  in  place  by  a  tissue  called  neuroglia, 
which  is  composed  "of  extremely  fine  fibers  and  minute  cells. 
Though  like  connective  tissue  in  function,  its  chemical  com- 
position is  different;  nor  is  neuroglia  developed  from  con- 
nective tissue  (Fig.  167). 

Terminations  of  nerve  fibers.  —  If  we  could  trace  toward 
the  central  nervous  system  the  course  of  the  various  nerve 
fibers  in  a  nerve  like  the  great  sciatic,  for  example,  we  should 
find  that  every  one  of  its  thousands  of  nerve  fibers  ends,  with- 
out exception,  in  a  nerve  cell  in  the  spinal  cord  or  brain, 
or  in  any  one  of  the  ganglia  near  the  central  nervous  system. 
If  we  should  trace  these  same  fibers  away  from  the  central 
nervous  system,  they  would  be  found  to  have  various  endings. 
Some  enter  the  muscles  where  they  subdivide,  and  finally 
end  in  the  muscle  cells.  Others  follow  the  blood  vessels 
and  end  in  the  muscle  fibers  forming  the  middle  layer  of 
their  walls.  Others  go  to  the  gland  cells ;  for  example,  the 
sweat  glands  in  the  skin.  Others,  passing  to  the  skin, 
terminate  at  the  roots  of  the  hair,  or  in  curious  little  bodies 
composed  of  cells  and  called  touch  corpuscles  (Figs.  169, 
170).  Depending  upon  its  function  every  nerve  fiber  ends 
centrally  in  a  nerve  cell  or  peripherally  *  in  either  a  muscle 
cell,  a  gland  cell,  or  a  sense  organ  cell.  Fibers  that  end  cen- 
trally are  sensory  and  carry  impulses  to  the  brain  or  cord ; 


2Q2 


Healthful  Living 


fibers  that  end  peripherally  are  motor  or  secretory  and  carry 
impulses  from  the  brain  or  cord. 

Efferent,*  afferent*  and  association*  fibers. — Fibers  that 
connect  nerve  cells  with  muscles  or  glands  are  called  effer- 
ent (outward  bearing)  fibers ;  (they  may  be  motor  or  secre- 
tory) ;  those  that  connect  nerve  cells  with  sense  organs  are 
called  afferent  (in  bearing)  fibers  (they  are  always  sensory). 

There   is   a  third   kind, 
^.  which  connects  nerve  cell 

with  nerve  cell  in  the 
brain;  they  are  known 
as  association  fibers. 

Nerve  action.  —  If  an 
afferent  nerve  be  irritated 
at  its  outer  endings  in 

afM^ssner     the    Cells    of    the    tisSUCS, 

an  impulse  will  travel  to 
the  brain  or  spinal  cord. 
If  it  goes  to  the  brain, 
consciousness  of  the  im- 
pulse will  be  apparent; 
if.  it  goes  only  as  far  as 
the  cord,  there  will  be 

FIG.   169.  —  Sens6ry  nerve  ending  in  skin,  i    PnnoPinilonp«?q   nf 

showing  tactile  corpuscle  of  Meissner. 

the  fact.     In  either  case 

there  may  be  a  motor  response  to  the  sensory  impulse  in 
the  form  of  a  reflex*  act.  Impulses  may  originate  in  the 
brain  and  pass  to  different  cells  in  the  body,  causing 
them  to  act.  This  occurs  when  one  consciously  makes  a 
muscular  movement.  Transmitting  nerve  impulses  is  the 
whole  duty  of  nerve  fibers.  The  endings  of  the  nerves  are 
so  abundant  in  the  skin  just  beneath  the  epithelium  that 
the  point  of  a  needle  cannot  enter  without  causing  pain. 
They  are  more  numerous  there  than  in  any  other  part  of 
the  body.  Afferent  nerves  are  not  so  abundant  in  the  muscles 


-Nerve 


The  Nervous  System 


293 


and  internal  organs  as  in  the  skin,  so  that  a  cut  gives  most 
pain  as  it  enters  the  skin  and  may  be  continued  into  deeper 
parts  with  only  slight  pain.  Efferent  nerves  begin  in  the 
nerve  cells  of  the  spinal  cord  and  end  in  the  muscles  and  glands 
of  the  body.  Efferent  nerves  and  efferent  impulses  have  three 
functions,  —  controlling  motion,  secretion,  and  growth. 
Because  of  this  multiplicity  of  function,  it  is  desirable  to 
call  them  efferent 
nerves  rather 
than  to  use  the  old 
term  "  motor." 
The  nerve  im- 
pulse, as  demon- 
strated in  the  frog, 
travels  about  100 
feet  per  second. 
This  is  the  speed 

of  an  PYnross  train 
1 

going  70  miles  an 

hour.     It  is  prob- 

able that  in  warm-blooded  animals,  such  as  man,  the  rate  is 

even  faster. 

General  sensations.  —  The  cells  of  the  body  are  constantly 
sending  impulses  to  the  central  nervous  system,  signifying 
their  needs.  These  impulses  give  rise  to  feelings  to  which 
the  mind  assigns  no  definite  location  in  the  body;  hence 
they  are  called  general  sensations.  Such  feelings  as  hunger, 
thirst,  fatigue,  and  sleepiness  belong  to  this  class.  They  are 
as  well  understood  by  a  baby  or  any  young  animal  as  by  a 
man,  and  unlike  the  special  sensations,  the  meaning  of  general 
sensations  does  not  have  to  be  learned,  as  the  memory  of 
them  owing  to  inherited  habit  seems  to  reside  in  the  nervous 
system.  General  sensations  are  sometimes  called  instincts. 

Special  sensations.  —  When  something  outside  of  the  body 
acts  upon  the  nerves,  it  produces  a  feeling  or  sensation  by 


FlG'  170.  —  Pacinian    body.     These   touch  end- 


ings  give  the  sense  of   pressure. 

dermis. 


Located   in   the 


294  Healthful  Living 

which  the  mind  forms  ideas  of  the  surroundings  of  the  body. 
The  meanings  of  these  feelings  must  be  learned  when  first 
perceived,  and  they  are  mostly  learned  in  childhood.  The 
special  senses,  taste,  sight,  smell,  pain,  temperature,  and 
muscular  sense,  are  of  such  importance  that  all  will  be  in- 
cluded in  a  separate  chapter. 

Injury  to  nerves.  —  If  motor  or  efferent  nerves  going  to 
a  muscle  are  cut,  there  is  paralysis  of  the  muscle,  so  that 
there  can  be  no  voluntary  or  reflex  action  in  the  part.  If  an 
efferent  nerve  going  to  a  gland  is  cut,  the  function  of  the 
gland  will  be  almost  suspended.  Even  if  food  is  taken  into 
the  mouth  and  the  sensory  nerves  carry  the  news  to  the 
brain,  the  efferent  nerve  being  cut,  no  impulse  can  return  and 
the  secretion  will  be  very  slight.  When  the  motor  nerve 
to  a  part  is  cut,  the  cells  will  be  almost  too  inactive  to  absorb 
and  carry  on  growth  and  repair ;  hence  unless  continually 
under  the  influence  of  motor  nerves  the  cells  dwindle  away. 
When  the  cells  are  much  used,  the  impulses  sent  cause  them 
to  take  in  more  nourishment  and  to  grow  in  size.  Thus  a 
muscle  increases  in  size  and  strength  when  much  used.  You 
learned  that  during  the  action  of  a. muscle,  the  vasomotor 
nerves  going  to  the  arteries  in  the  muscle  cause  what  change  ? 
Will  this  also  aid  in  growth  ?  When  a  nerve  is  cut,  the  ends, 
if  placed  together,  will  grow  again,  the  parts  supplied  by  it 
being  paralyzed  in  the  meantime. 

Nerves  may  become  inflamed,  and  the  disease  is  called 
neuritis,  just  as  inflammation  of  the  tonsils  is  called  ton- 
sillitis, or  of  the  stomach  is  called  gastritis.  Neuritis  of  the 
sciatic  nerve  is  called  sciatica;  it  is  a  very  painful  disease. 
One  of  the  many  dangers  of  using  alcohol  is  that  it  may 
produce  neuritis.  Either  slow,  steady  drinking  or  occasional 
"sprees"  may  cause  it.  The  disease  gives  no  warning  before 
it  comes,  and  may  remain  a  long  while.  Rheumatism  or 
malaria  may  also  cause  it,  but  alcohol  produces  the  disease 
as  often  as  all  other  causes  combined. 


The  Nervous  System 


295 


General    arrangement    of    the    nervous    system.  —  The 

brain  and  the  spinal  cord  make  the  central  nervous  system. 
The  nerves  coming  from  the  brain  are  the  cranial  *  nerves 
(Fig.  171).  There  are  twelve  pairs.  The  nerves  from  the 


{face  -Sensory 
Face-Motor 

Taste 


Spinal  Cord 
/st  Spfna/ Nerve 
-2d  Spina/ Nerve 

\ 


\^   L,iver 
*•»-...-* 


FIG.  171.  —  Diagram  of  the  twelve  cranial  nerves.  These  are  twelve 
pairs  of  cranial  nerves  which  arise  from  the  brain  and  go  out  through  the 
holes  in  the  lower  wall  of  the  skull.  (How  many  pairs  of  spinal  nerves 
are  there?)  The  cranial  nerves  are  numbered  according  to  the  location 
of  their  roots,  from  above  downward. 

cord  are  called  the  spinal  nerves.  There  are  thirty-one 
pairs  of  spinal  nerves.  These  nerves  running  from  the  central 
nervous  system  make  up  the  peripheral  system.  There  are 
other  nerves  connecting  mainly  the  involuntary  structures 
with  the  cord.  This  connection  is  made  by  nerves  that  end 
in  masses  of  nerve  cells  (ganglia)  lying  along  each  side  of 


296  Healthful  Living 

the  front  of  the  vertebral  column.  These  make  up  the 
autonomic*  system. 

The  spinal  cord.  Structure.  —  The  various  white  nerve 
fibers,  both  efferent  and  afferent,  of  the  entire  body  unite 
and  form  forty-three  pairs  of  larger  nerves ;  twelve  of  these 
pairs,  called  cranial  nerves,  go  to  the  brain,  and  thirty-one 
pairs,  called  spinal  nerves,  go  to  the  spinal  cord.  Each  one  of 
the  sixty-two  spinal  nerves  enters  the  spinal  cord  by  two 
roots,  one  posterior  and  one  anterior.  It  is  significant  that 
all  the  efferent  and  afferent  fibers  of  a  spinal  nerve  separate 
from  each  other.  The  efferent  fibers  enter  by  the  anterior 
root,  and  the  afferent  nerves  by  the  posterior  root  (Fig.  173) . 
The  afferent  fibers  do  not  really  enter  the  cord  but  end  in 
a  ganglion  on  the  posterior  root,  and  the  ganglion  sends 
dendrites  into  the  cord  by  the  posterior  root.  The  spinal 
cord  extends  from  the  foramen  magnum  "  or  great  open- 
ing," in  the  occipital  bone  down  to  about  the  second  lumbar 
vertebra.  What  parts  of  a  vertebra  form  the  canal  for  the 
cord?  Is  the  canal  made  of  bone  throughout  its  length? 
How  are  the  vertebrae  united  with  one  another  ? 

The  spinal  cord  is  about  the  size  of  the  little  finger.  It 
is  only  about  two  thirds  as  large  as  its  tube,  so  that  it  is  not 
likely  to  be  injured  by  bending  the  spinal  column.  The 
rest  of  the  space  in  the  canal  is  taken  up  by  a  lymphlike 
liquid,  and  three  membranes  called  meninges  which  form 
a  triple  covering  for  the  cord.  These  membranes  extend 
into  the  skull  and  cover  the  brain.  An  inflammation  of 
them  constitutes  a  very  serious  disease  called  cerebro-spinal 
meningitis. 

A  cross  section  of  the  spinal  cord  shows  that  it  is  a  double 
organ  (Fig.  172),  the  halves  being  united  by  a  narrow  por- 
tion ;  it  shows  also  that  the  central  part  of  the  cord  is  of 
gray  matter  in  the  outline  of  a  butterfly,  and  surrounded 
by  a  thick  layer  of  white  fibers.  The  gray  portion  is  made 
up  of  nerve  cells  that  give  off  fibers,  many  of  which  go  to  the 


The  Nervous  System 


297 


spinal  nerves  and  some  go  upward  in  the  outer  white  portion 
of  the  cord.     The  white  tract  also  contains  motor  threads 


Posterior  /foot 


White  Matte 


GrayMettt 


Anterior  Root        V 

FIG.  172.  —  Cross  section  of  the  spinal  cord.     Afferent  impulses  come  in 
over  the  posterior  root ;  efferent  impulses  go  out  over  the  anterior  root. 

that  bring  impulses  from  the  brain  to  the  cells  in  the  grajr 
matter. 

Function.  —  The  brain  sends  impulses  to  the  cells  in  the 
spinal  cord,  and  they,  being  aroused,  in  turn  send  motor 
impulses  to  the  muscles.  When  a  person  wills  to  move  his 
hand,  an  impulse  goes  to  the  spinal  cells,  and  they  in  turn 
send  impulses  that  cause  a  contraction  of  the  muscles  in 
the  arm.  The  brain  sends  about  ten  impulses  per  second 
to  keep  the  muscle  in  action.  Thus,  before  it  can  relax, 
another  impulse  reaches  it.  Each  muscle  has  its  own  set 
of  spinal  cells  in  the  cord  which  act  as  a  relay  station  be- 
tween the  muscle  and  the  brain.  The  cells  of  the  spinal 
cord  have  another  very  important  duty;  they  largely  con- 
trol reflex  action.  At  times  it  would  take  too  long  for  the 
brain  to  act,  so  the  body  needs  a  quicker  governing  power 
to  supply  its  needs  or  protect  it  from  injury.  If  the  finger 
touches  a  hot  object,  the  brain  becomes  conscious  of  the 


298  Healthful  Living 

burn  and  of  the  movement  of  the  finger  at  about  the  same 
time.  There  are  also  many  acts  that  are  performed  so  often 
that  the  spinal  cord  acquires  the  habit  of  sending  back  the 
appropriate  impulses.  Thus  muscles  and  other  organs  may 
be  controlled  and  the  brain  be  relieved  to  attend  to  other 
duties. 

The  same  motor  cells  of  the  spinal  cord  that  produce  mo- 
tion in  a  part,  also  exercise  an  oversight  that  controls  the 
growth  and  nutrition  of  the  cells  in  that  part.  The  impulses 
from  the  spinal  cells  furnish  a  constant  stimulus  to  growth 
and  repair. 

A  crumb  entering  the  larynx  brings  on  a  fit  of  coughing. 
A  dash  of  cold  water  makes  us  hold  our  breath.  A  pinch 
of  pepper  causes  us  to  sneeze.  If  the  foot  of  a  sleeping  person 
is  tickled,  he  will  kick;  if  a  fly  settles  on  his  face,  he  will 
brush  it  off.  Sometimes  a  person  in  an  unconscious  con- 
dition will  drink  a  cup  of  water  if  it  is  placed  to  the  lips. 

If  the  back  is  broken,  reflex  actions  persist  although  all 
sensation  and  volition  concerning  the  parts  below  the  injury 
are  suspended.  The  leg  will  kick  when  the  foot  is  tickled, 
etc.  A  surgeon  tickled  the  foot  of  a  man  whose  spinal  cord 
was  injured,  and  the  feet  kept  up  a  vigorous  kicking.  He 
asked  the  man  if  he  felt  it ;  he  said,  "  No,  but  you  see  that 
my  feet  do."  On  carefully  testing  the  sensibility  of  such 
a  man,  a  line  can  be  traced  girdling  the  body,  dividing  the 
sensitive  from  the  insensitive  part.  The  brain  also  may 
act  seemingly  in  a  reflex  manner  as  in  cases  of  somnambulism, 
or  sleep-walking. 

When  one  is  learning  new  movements,  such  as  walking, 
skating,  writing,  riding  a  bicycle,  each  movement  is  a  vol- 
untary one  as  far  as  the  will  is  capable  of  watching  so  many 
muscles,  The  movements  are,  therefore,  slow  and  awkward. 
After  the  movements  have  been  made  many  hundreds  of 
times,  they  become  easy  and  graceful,  and  also  less  vol- 
untary. This  is  accomplished  by  the  nerve  impulse  select- 


The  Nervous  System  299 

ing  the  pathway  that  gives  the  right  response.  At  first 
many  pathways  are  used  and  tried.  When  the  pathway  is 
found  that  gives  the  result  sought  and  there  is  pleasure  in 
the  reaction,  then  the  movement  is  learned  and  it  becomes 
easy  and  graceful. 

We  must  not  think  of  reflexes  as  being  only  related  to 
muscles  and  movement.  They  may  have  a  character  that 
prevents  or  suppresses  movement.  A  dash  of  cold  water 
on  the  chest  will  inhibit  respiration.  A  sudden  emotional 
shock  may  be  so  terrifying  as  to  prevent  muscular  contraction 
and  one  will  stand  still  in  the  face  of  great  danger.  Reflex 
activity  of  glands  is  often  not  related  to  movement.  The 
secretion  of  tears,  caused  by  a  cinder  in  the  eye,  is  reflex. 
The  impulse  is  carried  to  the  lachrymal  (tear)  gland  by  the 
secretory  nerves.  These  nerves  are  efferent  but  not  motor. 

Education  of  reflex  action  consists  mainly  of  the  forma- 
tion of  habits.  The  impression  on  the  nervous  system  from 
the  training  is  made  chiefly  on  the  spinal  centers.  When  the 
muscles  of  the  hand  are  educated,  it  is  really  the  spinal  cells 
that  are  educated.  During  youth,  one  is  always  acquiring 
good  habits  or  bad  habits.  The  habit  of  an  upright,  easy 
walk,  the  habit  of  dropping  into  a  stooping  posture,  of  putting 
the  hands  in  the  pockets,  of  making  wry  faces,  of  mumbling 
and  stammering,  or  of  talking  distinctly  and  without  hesi- 
tation, may  be  acquired,  and  will  probably  remain  through 
life,  for  impressions  made  on  the  nervous  system  in  youth 
are  lasting.  The  habit  of  eating  temperately  of  pure  food, 
the  habit  of  stuffing,  of  awaking  the  nerves  with  stimulat- 
ing condiments,  of  using  alcoholic  stimulants,  of  using 
tobacco,  are  easily  acquired,  but  are  lost  with  difficulty. 
Good  habits  are  good  friends ;  bad  habits  are  enemies.  It 
often  requires  years  of  constant  effort  to  root  out  bad  habits, 
but  it  is  very  easy  to  keep  them  out  in  the  first  place;  Yet 
if  the  wish  and  will  for  a  better  habit  is  really  strong,  one 
need  never  despair,  for  on  account  of  the  large  size  and  great 


300  Healthful  Living 

activity  of  the  brain,  and  its  preponderance  over  the  lower 
reflex  centers,  man  is  distinguished  above  all  other  animals 
by  his  power  of  forming  new  habits.  If  our  ideals  are  high, 
we  can  go  on  forming  better  habits,  and  intrusting  them  to 
the  keeping  of  the  nerve  centers,  and  thus  make  step  after 
step  toward  our  ideal.  If  our  ideals  are  not  high,  or  if  they 
are  mere  theories  and  never  affect  our  acts,  we  may  never 
improve,  but  may  even  degenerate: 

The  autonomic  system.  —  The  nerves  coming  off  from  the 
spinal  cord  and  going  to  the  muscles  are  called  the  spinal 
or  skeletal  nerves.  Those  coming  from  the  brain  are  called 
the  cranial  nerves.  There  are  other  nerves  which  innervate 
the  organs  of  the  body  and  these  come  from  both  spinal  cord 
and  brain.  At  one  time  they  were  called  "  sympathetic* 
nerves  "  but  now  the  name  autonomic  is  given  to  these 
nerves.  They  supply  the  viscera,  blood  vessels,  glands,  and 
hair.  It  is  seen,  therefore,  that  skeletal  muscles  receive 
their  stimulation  from  the  central  nervous  system  and  the 
involuntary  muscles  of  the  body  receive  their  stimulation 
from  the  autonomic  system.  Now  the  motor  nerves  supply- 
ing the  skeletal  muscles  come  from  cells  which  lie  in  the 
ventral  part  of  the  spinal  cord ;  the  glands  and  smooth 
muscle  of  the  viscera  receive  their  innervation  from  nerves 
which  come  from  ganglions  which  lie  outside  the  spinal  cord. 
The  difference  between  the  two  systems  in  type  is  shown  in 
Figure  173.  The  neurons  running  to  the  visceral  organs 
usually  have  their  cell  bodies  grouped  in  ganglia  and  this 
arrangement  gives  rise  in  certain  places  to  a  mass  of  nerve  tis- 
sue which  receives  the  name  plexus.  Hence,  we  have  the  solar 
plexus,  the  cardiac  plexus,  the  splenic  plexus,  etc.  (Fig.  175). 
The  ganglia  and  plexuses  of  the  autonomic  system  are  con- 
nected with  the  brain  and  spinal  cord  by  neurons  whose  cell 
bodies  lie  within  the  spinal  cord.  It  is  to  be  noticed,  therefore, 
that  there  are  two  sets  of  neurons  of  this  system ;  one  from 
the  cord  and  brain  to  the  ganglion  sometimes  called  the  pre- 


The  Nervous  System 


301 


ganglionic  neuron ;  and  one  from  the  ganglion  to  the  viscera 
and  gland  and  sometimes  called  the  postganglionic  neuron. 
This  arrangement  is  shown  in  Figure  174.  This  figure  should 
be  studied  with  reference  to  the  arrangement  of  the  three 
divisions  of  this,  system.  The  name  autonomic  has  been 
suggested  by  Langley  and  indicates  that  the  structures 


Post-Gangfionfc  Fiber 


Post-Ganqtionic 


Gang/ion  of 
'ufonom/c  System 


FIG.  173.  —  The  preganglionic  fibers  of  the  autonomic  system  leave 
the  motor  root  and  run  to  the  ganglion. 

supplied  by  these  nerves  are  not  under  voluntary  control. 
In  addition  only  a  part  could  be  classed  under  the  old  head- 
ing of  sympathetic.  So  it  is  that  there  are  given  three 
divisions,  the  thoracico-lumbar  *  (sympathetic),  the  cranial, 
and  the  sacral.* 

Thoracic-Lumbar  Division.  —  The  second  division  has 
the  largest  distribution.  It  sends  fibers  to  the  eyes  and 
causes  dilatation  of  the  pupils.  To  this  division  belong  the 
accelerator  nerves  that  go  to  the  heart  (Figs.  174,  175). 
They  cause  it  to  beat  faster.  They  also  carry  impulses  to 


—  Artery  of  Salivary  G/and 


y—  -  Surface  Artery 
Sweat  G/and 


rtery 


FIG.  174.  —  Diagram  of  the  important  parts  of  the  autonomic  nervous 
system,  (a)  preganglionic  fibers ;  (6)  postganglionic  fibers ;  (c)  plexus ; 
(d)  ganglia  situated  outside  the  cord;  spinal  cord  and  medulla  and  the 
parts  to  which  the  fibers  go. 

302 


The  Nervous  System 


303 


the  muscle  of  the  arteries  and  so  make  possible  vaso-con- 
striction.  The  stimulation  of  the  fibers  which  go  to  the 
muscles  of  the  hair  causes  the  hair  to  stand  on  end.  It  is 
also  known  that  the  stimulation  of  these  nerve  fibers  occurs 


Spinal  Ganglia 


Spinal  Ganglia 


Spinal  Ganglia 


Cardiac  Plexus 


Solar  Plexus 


-ffypotjastric  Plexus 


FIG.  175.  —  Diagram  of  trunk  showing  one  of  the  two  rows  of  autonomic 
ganglia  near  the  spinal  column  and  the  plexuses. 

under  conditions  which  call  forth  emotional  reactions.  For 
example,  when  one  is  afraid,  the  hair  stands  on  end;  de- 
pressing conditions  cause  the  flow  of  tears;  the  heart  rate 
is  increased  at  times  of  emotional  disturbance. 


304  Healthful  Living 

Cranial  Division.  —  The  cranial  autonomic  serves  to 
protect  the  body  and  to  conserve  its  strength.  The  main 
part  of  the  cranial  division  is  the  vagus  nerve  which  runs 
to  the  heart  and  all  the  abdominal  organs  (Fig.  174).  The 
cranial  autonomic  goes  also  to  the  salivary  gland  and  causes 
it  to  secrete  more  saliva.  It  slows  the  heart  and  causes 
the  contraction  of  the  pupil.  An  analysis  of  these  functions 
will  show  that  this  division  serves  to  conserve  the  body. 
By  slowing  the  heart,  the  cardiac  muscle  is  given  a  chance  to 
rest ;  by  contracting  the  pupil  the  retina  is  protected ;  by 
stimulating  the  flow  of  saliva,  gastric,  and  other  digestive 
juices  and  by  causing  the  contraction  of  the  smooth  muscle 
of  the  viscera,  all  the  processes  of  digestion  are  accelerated 
and  energy  is  produced  with  the  least  expenditure  of  energy. 
This  makes  for  conservation  of  strength  and  reserve  force. 

Sacral  Division.  —  The  sacral  division  provides  for  the 
contraction  of  the  smooth  muscles  concerned  in  emptying 
the  organs  which  hold  the  waste  of  the  body.  These  nerves 
control  the  action,  therefore,  of  the  colon,  rectum,  and 
bladder.  This  section  may  be  thought  of  as  rendering  serv- 
ice to  the  body  by  keeping  the  waste  removed  and  so  it  is 
of  importance  in  body  health  and  conservation. 

Antagonism  between  the  Sympathetic  Division  and  the 
Cranial  and  Sacral.  —  This  very  complex  mechanism  for 
controlling  the  involuntary  action  of  the  bodily  processes 
has  a  very  interesting  action,  in  that  there  is  antagonism  be- 
tween the  ends  and  central  part  of  the  system.  Cannon 
says,  "  When  the  mid-part  meets  either  end  part  in  any 
viscus  their  effects  are  antagonistic."  For  example,  the 
cranial  fibers  contract  the  pupil,  the  sympathetic  fibers 
dilate  it.  The  cranial  fibers  (the  vagus)  slow  the  heart,  the 
sympathetic  (the  accelerator  nerves)  accelerate  the  heart. 
These  opposed  effects  are  indicated  in  Figure  174  in  which 
+  means  contraction,  acceleration,  and  —  means  relaxation, 
retardation. 


The  Nervous  System  305 

Functions  of  the  Autonomic  System.  —  It  is  important  to 
understand  the  working  of  this  mechanism  and  to  see  how 
this  knowledge  can  guide  us  in  shaping  our  lives  so  that  we 
may  act  in  harmony  with  the  mechanism  of  our  bodies  and 
not  against  it.  It  is  always  of  value  to  act  in  accordance 
with  the  laws  of  health  as  well  as  the  laws  of  the  nation. 
From  an  understanding  of  this  autonomic  system,  we  ap- 
preciate why  it  is  desirable  to  be  happy  and  cheerful  at  meal- 
times in  particular.  Emotional  disturbance  near  meal  times 
interferes  with  digestion  because  the  sympathetic  fibers 
carry  the  impulses  concerned  in  rage,  anger,  fear,  .or  pain," 
and  these  impulses  will  interfere  with  the  impulses  sent  by 
the  cranial  division,  supplying  the  digestive  juices.  So  it 
is  that  all  the  processes  of  the  body  are  assisted  and  accel- 
erated by  conditions  that  are  cheerful.  Happiness  is  a 
desirable  stimulant  and  will  work  marvelously  to  keep  the 
body  well.  One  should  not  give  expression  to  feeling  of 
crossness,  sullenness,  pouting,  anger,  etc.  Beyond  the  fact 
that  they  injure  the  body,  of  more  importance  is  the  fact 
that  they  make  other  people  unhappy. 

Afferent  Nerves  of  the  Autonomic  System.  —  The  afferent 
impulses  through  these  nerves  are  slow  and  faint,  seldom 
reaching  beyond  the  spinal  ganglia  to  the  brain.  Thus  the 
circulation  of  the  blood  and  the  digestion  of  the  food  usually 
go  on  without  our  consciousness,  but  a  very  strong  irrita- 
tion may  give  rise  to  consciousness  and  pain  in  the  abdominal 
organs,  as  in  colic  or  in  vomiting.  Sensory  impulses,  signify- 
ing the  needs  of  the  cells  and  the  necessity  for  movement  in 
the  arteries  and  intestines,  are  being  continually  sent  to  the 
spinal  ganglia  (Fig.  175).  Only  very  strong  impulses  caused 
by  disturbances  that  may  injure  the  body,  reach  the  brain, 
and  cause  pain. 

Efferent  Nerves  of  the  Autonomic  System.  —  The  efferent 
nerves  carry  impulses  which  cause  the  epithelial  cells  of 
the  glands  to  make  their  secretions,  and  the  muscles  of  the 


306  Healthful  Living 

arteries  and  intestines  to  contract.  They  do  this  as  a  re- 
flex response  to  the  impulses  going  to  the  spinal  ganglia 
from  the  sensory  nerves  of  the  system.  At  a  flash  of  bright 
light  the  eye  winks  and  the  pupil  contracts.  The  sweat 
glands  secrete  under  the  influence  of  warmth.  It  was 
formerly  believed  by  physiologists  that  the  "  sympathetic " 
ganglia  themselves  sent  the  reflex  motor  impulses,  but  it  is 
now  believed  that  these  come  from  the  spinal  ganglia.  The 
"sympathetic"  ganglia  are  supposed  to  reenforce  the  current 
and  aid  in  the  nutrition  of  the  nerves  that  pass  through 
them. 

The  brain.  —  The  spinal  cord  can  act  only  in  response 
to  impulses  at  the  moment  they  are  received.  The  brain 
can  originate  impulses  which  are  not  in  direct  response  to  a 
stimulus  from  the  outer  world.  Its  acts  are  apparently 
spontaneous,  but  they  probably  result  from  the  combination 
of  impulses  previously  received,  which  memory  has  enabled 
it  to  store  up  and  retain.  The  brain  not  only  causes  action 
and  directs  the  cord  in  giving  order  to  voluntary  movements, 
but  it  can  restrain  excessive  action  in  the  spinal  cord.  Self- 
control  comes  largely  through  the  power  possessed  by  the 
brain  of  restraining  the  spinal  cells  from  sending  out  reflex 
impulses  when  strong  and  sudden  impulses  are  received 
from  the  outer  world.  This  is  called  the  inhibitory  power. 
If  a  door  slams,  a  person  whose  brain  is  not  exerting  good 
control  jumps  suddenly. 

Coverings  of  the  Brain.  —  What  facts  did  you  learn  about 
the  skull,  showing  that  it  is  well  constructed  for  protecting 
the  brain  ?  The  brain  is  covered  by  three  membranes ;  the 
outer  tough  one  lines  the  skull  and  the  spinal  canal.  The 
next  is  thinner.  There  is  a  lymphlike  fluid,  called  the 
cerebro-spinal  fluid,  within  this  membrane,  so  that  the  brain 
is  surrounded  by  a  kind  of  water  bed.  The  third,  and  inner- 
most, covering  is  hardly  a  membrane,  for  it  is  merely  a  thin 
network  of  fine  blood  vessels  and  connective  tissue.  It  dips 


The  Nervous  System  307 

down  into  every  depression  and  fold  of  the  outer  layer  of 
gray  cells  of  the  brain.  This  layer  of  gray  matter  is  called 
the  cortex.  The  folds  in  it  are  called  convolutions  (See 
Plate  VII).  Numerous  folds  signify  great  intelligence. 

Weight.  —  The  weight  of  the  brain  of  the  average  man  is 
forty-nine  ounces  (a  little  over  three  pounds),  and  of  the 
average  woman  is  forty-four  ounces.  The  woman's  brain 
is  as  large  in  proportion  to  the  size  of  her  body  as  a  man's 
brain.  Man's  brain  is  surpassed  in  weight  by  the  brains  of 
only  two  animals.  A  whale,  measuring  seventy  feet  long, 
has  a  brain  weighing  only  five  pounds,  and  an  elephant's 
enormous  body  is  controlled  by  a  brain  of  about  eight  pounds. 
Birds'  brains  are  heavier  in  proportion  to  their  bodies  than 
the  brain  of  any  other  animal.  The  brain  grows  very 
rapidly  till  the  fifth  year,  then  very  slowly;  the  growth 
after  twenty  is  very  slight.  Cromwell's  brain  is  said  to  have 
weighed  almost  eighty  ounces.  Other  great  men  have  had 
large  brains,  but  some  great  minds  have  inhabited  very 
small  brains.  Quality  is  as  important  as  quantity.  The 
brains  of  idiots  are  usually  very  small. 

The  Cerebrum.  —  The  chief  parts  of  the  brain  are  the 
cerebrum,  the  cerebellum,  and  the  medulla  oblongata.  The 
cerebrum,  or  great  brain,  divided  by  a  cleft  into  two  parts, 
is  highest  in  the  skull,  and  covers  all  the  other  parts 
(Plate  VI) .  It  is  composed  of  cells  which  lie  in  the  cortex 
and  fibers  which  pass  from  the  cells  to  and  from  the  spinal 
cord  and  cranial  nerves  (Figs.  176,  177).  Sense-perception, 
consciousness,  reason,  and  the  will  are  located  in  the  cerebrum. 
The  cerebrum,  as  all  other  organs,  is  dependent  upon  circula- 
tion, respiration,  digestion,  and  excretion.  If  the  heart  sud- 
denly weakens  its  action  very  much,  or  if  the  vasomotor 
nerves  allow  the  arteries  to  lose  tone  suddenly  and  increase 
their  capacity  for  blood,  the  person  faints,  from  a  weakening  of 
the  circulation  through  the  brain.  Recovery  is  brought  about 
by  placing  the  head  on  a  lower  level  than  the  body,  so  that 


3o8 


Healthful  Living 


the  blood  may  run  to  the  brain  with  less  exertion  on  the  part 
of  the  heart.  A  violent  blow  on  the  head  may  make  one 
insensible  at  once.  By  breathing  chloroform,  ether,  or 

carbon  dioxide,  by  taking  mor- 
phine, the  quality  of  the  blood 
may  be  so  altered  as  to  bring 
sleep.  In  order  that  the  brain 
may  act,  it  must  be  constantly 
aroused  by  impulses  from  the 
outer  world.  Man  loses  con- 
sciousness as  soon  as  his  cerebral 
hemispheres  cease  to  act ;  but 
his  heart  and  lungs  keep  at  work. 
It  is  curious  that  touching  the 
cerebrum,  or  stimulating  it  with 
electricity,  when  it  has  been  ex- 
posed by  accident,  arouses  no 
sensation,  although  this  organ  is 
believed  to  be  the  seat  of  con- 
sciousness. This  fact  is  of  great 
interest,  for  it  shows  that  im- 
pressions coming  from  the  sense 
organs  alone  enter  into  conscious- 
.  ,.  ness.  Fresh  air,  good  food,  and 

FIG.  176.  —  Microscopic  dia-  .  ' 

gram  of  the  cells  in  the  cortex  pure  blood  are  essential  for  the 
of  the  cerebrum,  a  external  best  functioning  of  the  cerebrum. 

layer  showing  association   cell,  '         . 

axone,   and   dendrites ;    6,   py-          Effect  of  Removing  Cerebrum. 

ramidai  cell  which  sends  off    _After  destruction  of  the  cere- 

axone    to    enter    the    layer    of  m 

meduiiated  fibers  c.    The  den-    brum,  an  animal  may  continue  to 

drites  of  the  pyramidal  cells  R  tf  f  d  b  h  d  jt  can  run 
pass  into  layer  a.  J 

about,  and  swallow  food  placed 

within  its  mouth.  It  will  be  disturbed  by  a  loud  sound, 
such  as  the  blowing  of  a  horn.  It  might  avoid  a  bright 
flame  if  placed  in  its  path,  but  would  go  stupidly  against 
other  objects;  but  it  is  idiotic,  for  all  acts  of  intelligence 


TJte  Nervous  System 


3°9 


cease.  Its  time  is  spent  in  sleep  or  mechanical  wandering. 
A  frog  deprived  of  its  cerebrum  retains  some  more  extensive 
powers  than  a  warm-blooded  animal.  It  starts  to  hopping 
when  touched, 
avoids  obstacles 
in  its  path,  re- 
covers its  usual 
position  when 
placed  on  its  back, 
swims  when 
thrown  into  water, 
and  when  placed 
on  a  board  that  is 
slowly  tilted,  it 
will  preserve  its 
balance  by  climb- 
ing to  the  top. 
These  actions  are 
reflex  but  of  a 
higher  order  than 
a  simple  reflex  act. 
The  reason  the 
frog  continues 
hopping  after  be- 
ing touched  is  that 
each  hop,  owing 
to  the  contact  of 
the  skin  with  the 
ground,  excites 


FIG.   177.  —  Diagram  of  the  motor  area  and  the 


another  hoD  •    the    motor  tract  in  the  brain.     Find  centers  for  leg,  arm, 

animal  never  be- 
gins to  move  of  its 
own  accord. 

Centers   in   the 
Cerebrum     (Figs. 


face.  Notice  that  most  of  the  motor  fibers  from 
one  hemisphere  cross  to  the  opposite  side  of  the 
spiral  cord ;  and  if  one  half  of  the  brain  is  injured, 
the  opposite  half  of  the  body  loses  motion  and 
sensation  (paralysis).  Trace  nerve  impulse  from 
cell  1  in  cortex  at  c  to  muscle  at  6  (1-3).  Trace 
reflex  impulse  from  skin  at  a  to  muscle  at  b  (4,  5, 

6, 3). 


3io 


Healthful  Living 


178,  179,  180).  — When  the  part  of  the  cerebrum  that  lies 
behind  the  ear  is  destroyed,  a  loss  of  the  memory  for  the 
meaning  of  words  may  result.  One  can  speak,  but  his  words 
follow  each  other  without  sense  or  meaning.  The  sense  of 
hearing  is  supposed  to  be  located  in  the  same  region.  The 
sense  of  sight  is  located  in  the  rear  part  of  the  cerebrum.  If 


FIG.   178.  —  Localized  areas  of  the  cortex. 

the  rear  part  of  the  left  hemisphere  is  destroyed,  a  man  is 
unable  to  see  anything  to  the  right  of  his  nose  when  his  eyes 
are  directed  straight  forward.  The  sense  of  smell  lies  at  the 
base  of  the  cerebrum  toward  the  front  (Figs.  179,  181). 

A  wounded  soldier  was  brought  to  the  surgeons  with 
part  of  his  skull  torn  away.  The  surgeons  used  an  electric 
current  to  test  whether  the  nerves  were  paralyzed.  They 
were  astonished  to  find  that  whenever  the  electric  current 
was  applied  to  the  wounded  part  of  the  head,  muscular 


The  Nervous  System 


movements  were  excited.     It  was  soon  determined  that  by 
stimulating    electrically    a    certain    area    of    the    cerebral 
cortex  movements  on 
the  opposite  side  of  the 
body  can  be  excited. 
This  area,  called  the 
motor  area  (Fig.  178), 
lies  under  the  parietal 
bone,      and      extends 
from  the   top   of  the 
brain  to  the  level  of 
the   ear.     By   experi- 
ments     On      monkeys        FlG-    179-  ~  View    of    one    cerebral    hemi- 
1  .       ,         sphere  from  between  the  hemispheres  showing 

and      dOgS,      and       by    motor  and  sensory  centers. 

studying  cases  of  acci- 
dents to  the  skull  in  human  beings,  this  area  has  been  sub- 
divided.    Stimulation  of  the  lowest  part  causes  movements 

of  the  face ;  of  the 
middle  part,  the 
arm ;  and  of  the 
upper  part,  the  leg, 
the  movement  al- 
ways being  on  the 
side  opposite  to  the 
stimulation  (Fig. 
180).  When  the 
lowest  part  of  the 
area  on  the  left  side 
in  right-handed  per- 
sons is  injured,  the 

Fio.  180.  —  Motor  and  sensory  centers.     Most    power    of    speech    is 
centers  occur  in  both  hemispheres,  and  if  one  is    ,  m, 

injured,  the  other  will  continue  to  work.  lost.       Ihe     Compre- 

hension     of     words 

and  the  ability  to  write,  read,  and  hear  language  is  not  lost. 
With  left-handed  persons,  this  center  is  on  the  right  side. 


312  Healthful  Living 

The  Cerebellum.  —  The  cerebellum,  or  small  brain,  is  at 
the  base  of  the  skull  behind.  If  a  pigeon  has  its  cerebellum 
removed,  it  is  restless  and  has  wide-open  eyes;  it  flutters, 
but  cannot  fly.  If  the  cerebrum  is  removed,  leaving  the 
cerebellum,  it  is  stupid,  but  flies  if  thrown  into  the  air.  By 
placing  the  hand  at  the  back  of  the  skull  between  the  occiput 
and  the  neck,  you  will  cover  the  part  occupied  by  the  cere- 
bellum. Coordination  of  the  muscles  is  carried  out  by  the 
cerebellum.  You  will  to  walk  through  activity  of  the  cere- 
brum ;  the  control  of  the  muscles  while  walking  is  the  function 
of  the  cerebellum. 

Function  of  the  Cerebellum.  —  The  removal  of  the  whole 
of  the  cerebellum  from  an  animal  does  not  produce  death 
so  long  as  the  medulla  is  not  injured,  but  the  animal  becomes 
weak  and  unsteady  in  its  movements.  If  the  cerebrum  re- 
mains, the  mental  faculties  are  retained.  Disease  of  the 
cerebellum  in  man  produces  dizziness  and  leads  to  a  stagger- 
ing, reeling  gate.  Hence  it  is  believed  that  the  function  of 
the  cerebellum  is  to  aid  the  cerebrum  in  the  control  of  the 
muscles.  It  brings  about  proper  coordination  of  the  muscu- 
lar movements,  so  that  in  such  movements  as  standing, 
walking,  talking,  the  different  muscles  may  each  act  at  the 
right  moment  and  with  due  force.  The  spinal  cord  also 
coordinates  movements.  For  instance,  if  a  frog  is  decapi- 
tated and  left  quiet  for  an  hour  or  two,  so  that  the  spinal 
cord  may  recover  from  the  shock  due  to  the  injury,  it  may 
be  made  to  execute  seemingly  purposeful  movements.  If  a 
drop  of  acid  be  placed  on  the  flank  of  such  a  frog,  the  leg 
will  be  drawn  up  and  the  acid  wiped  off  with  the  toes.  But 
such  coordinated  movements  are  not  accompanied  by  con- 
sciousness. 

The  Medulla  Oblongata.  —  This,  the  most  important  of 
the  cerebral  ganglia,  may  be  looked  upon  as  the  part  of  the 
spinal  cord  within  the  skull.  It  is  just  within  the  foramen 
magnum,  and  is  intermediate  in  position  and  function  be- 


The  Nervous  System 


313 


0/fBCtory 


O/ factory 
~  Bulb 


tween  the  brain  and  spinal  cord.     The  spinal  cord  acts  re- 

flexly;  the  brain  acts  consciously.     Conscious  actions  are 

those  which  are  influenced  by  mental  images  or  ideas.     The 

medulla  contains  reflex  centers  and  the  centers  of  automatic 

action.     This  kind  of  action  should  not  be  confused  with 

acquired  reflexes,  such  as  walking,  to  which  the  term  "auto- 

matic" is  sometimes  applied.     Automatic  centers  are  those 

which  are  con- 

trolled   by    the 

condition  of  the 

blood.  They  are 

stimulated     by 

an    increase    of 

carbon    dioxide 

in    the     blood. 

The     chief     of 

these  centers  is 

the    respiratory 

center    of     the 

medulla        If    it  ^IQ>  ^^'  —  ^e  °^act°ry  nerve.     The  main  nerve 

.     .    .        *  ends  in  the  form  of  a  bulb  on  the  floor  of  the  skull. 

IS  injured,  death  The  fibers  branch  from  this  bulb  like  the  roots  from 

ensues  bv  Sllffo-  an  omon  and  spread  out  on  the  walls  of  the  nasal 

k  chamber. 

cation.      The 

cerebellum  or  even  the  cerebrum  may  be  injured  or  removed 
from  the  lower  animals  without  causing  death,  but  the 
smallest  injury  to  the  respiratory  center  kills  the  animal 
immediately.  In  cases  of  hanging,  it  is  injury  to  this  center 
that  causes  death.  Another  very  important  center  in  the 
medulla,  controlled  by  automatic  action,  that  is,  by  the 
varying  condition  of  the  blood,  is  the  center  for  vasomotor 
nerves,  which  regulate  the  size  of  the  blood  vessels.  It  was 
previously  learned  that  the  vasomotor  fibers  belong  to  the 
autonomic  system.  There  are  also  important  reflex  centers 
in  the  medulla,  viz.,  the  centers  for  the  secretion  of  saliva. 
for  swallowing,  for  vomiting. 


314 


Healthful  Living 


Mucous    Membrane 


How  Automatic  Centers  Work.  —  As  the  blood  becomes 
deficient  in  oxygen  and  charged  with  carbon  dioxide,  the 
respiratory  center  is  irritated  and  sends  out  impulses  which 
cause  deeper  breathing.  This  improves  the  condition  of  the 
blood,  and  the  respiration  is  quieter  until  the  blood  again 
loses  oxygen;  then  stronger  impulses  are  sent,  and  so  on, 

thus  regulating 
the  condition  of 
the  blood  auto- 
matically. The 
size  of  the  blood 
vessels  is  regu- 
lated in  the  same 
way  by  the  vas- 
omotor  center  in 
the  medulla,  in- 
crease of  carbon 
dioxide  causing 
contraction  of  the 

FIG.  182.  —  Diagram  of  a  salivary  gland.     Showing 

automatic  control  (after  Landois  and  Sterling).         SUriace       Vessels, 

decrease     of     it 

causing  relaxation.  Automatic  acts  take  place  in  series. 
Reflex  acts,  such,  for  example,  as  walking,  can  take  place 
in  series  also,  but  the  first  stimulus  in  reflex  acts  comes  from 
without  the  body ;  in  automatic  acts  from  the  blood.  Fig- 
ure 182  shows  how  a  center  controlling  the  secretion  in  a 
gland  may  receive  impulses  from  the  mucous  membrane, 
from  the  brain,  and  then  impulses  are  sent  to  the  blood 
vessel  to  dilate  and  supply  more  blood  and  to  the  gland  to 
begin  to  secrete. 

GLOSSARY 

Afferent    (nerves).  —  Conducting   inward    toward    the    cord    and 

brain. 
Association.  —  Refers  to  nerve  fibers  that  are  concerned  in  purposely 

connecting  different  nerves  or  brain  areas. 


The  Nervous  System  315 

Autonomic.  —  Entirely  independent  and  self-supporting  in  itself. 

Cranial.  —  Relating  to  the  cranium  or  the  organ  within  the  cranium, 
the  brain. 

Dendrites.  —  The  tree-like  branches  of  a  nerve  cell.  The  den- 
drite  receives  the  nerve  impulse  from  the  axon. 

Efferent  (nerves).  —  Conducting  away  from  the  cord  and  brain. 
All  efferent  impulses  are  not  motor  and  so  efferent  and  afferent 
are  more  desirable  terms  than  motor  and  sensory. 

Medullated.  —  Covered  with  a  soft  fatty  substance ;  that  is,  covered 
with  a  medulla. 

Neuron.  —  A  nerve  cell  with  its  dendrites  and  axon  and  hence  the 
structural  unit  of  the  nervous  system. 

Peripherally.  —  Away  from  the  center. 

Reflex.  —  An  act  that  goes  on  without  the  direction  of  the  brain. 
It  occurs  before  the  individual  is  hardly  conscious  of  the  act. 
He  may  be  conscious  afterwards  that  he  has  acted  but  he  has 
given  no  direction  in  the  process. 

Sacral.  —  Relating  to  the  sacrum,  near  the  sacrum  or  coming  from 
the  sacrum. 

Sympathetic.  —  A  part  of  the  nervous  system  of  the  body  that 
originally  was  supposed  to  be  concerned  in  acts  that  were  of 
a  sympathetic  character.  The  name  now  is  autonomic  be- 
cause it  is  known  that  the  chief  characteristic  of  this  sys- 
tem is  the  ability  to  carry  on  its  activities  without  direc- 
tion or  help.  Also  its  activities  involve  more  than  was 
connoted  by  the  term  "  sympathetic." 

Thoracico-lumbar.  —  A  compound  word  referring  to  the  thoracic 
and  lumbar  regions  of  the  vertebral  column. 


CHAPTER  XVI 
HYGIENE    OF   THE   NERVOUS    SYSTEM 

I.    Connection  between  Body  and  Mind. 
II.    The  Effect  of  Activity  on  the  Nervous  System. 

III.  The  Effect  of  Sleep. 

IV.  The  Effect  of  Fatigue. 
V.    The  Effect  of  Alcohol. 

VI.    Improper  Functioning  of  the  Nervous  System. 
Drugs  and  insanity 
Communicable  disease  and  insanity 
Habits  of  mind  and  insanity 
VII.   Ten  Golden  Rules  of  Health  for  School  Children. 


Connection  between  body  and  mind.  —  The  body  and  the 
mind  are  very  closely  related,  are  interdependent  and 
are  a  unit.  We  have  learned  that  muscle  and  nerve  are 
interdependent.  So  it  is  with  mind  and  body.  Only  rarely 
do  you  find  a  fine  mind  in  a  poor  body;  and  in  such 
an  instance,  the  individual  has  lost  largely  the  quality  of 
bodily  vigor  which  enables  him  to  perpetuate  his  greatness. 
This  unity  of  body  and  mind,  this  balance  of  physical  and 
mental  powers  is  essential  for  the  welfare  of  the  race. 
Men  and  women  should  not  only  preserve,  but  if  possible  im- 
prove the  quality  of  life  they  have,  so  that  the  race  will  be  en- 
riched. There  are  many  familiar  examples  of  the  connection 
between  mind  and  body.  Most  men  who  have  been  great 
workers  with  their  minds  have  also  been  zealous  in  using 
their  muscles.  There  is  a  flexibility  of  mind  and  disposition 
that  results  from  a  mixed  occupation  which  is  in  great  con- 
trast with  the  machine-like  dullness  and  narrowness  of  mind 

316 


Hygiene  of  the  Nervous  System  317 

produced  by  a  monotonous,  one-sided  occupation,  whether 
mental  or  physical.  Gladstone  chopped  down  trees;  Li 
Hung  Chang  when  eighty  years  old  walked  three  miles  daily 
around  the  courtyards  of  his  palace ;  Napoleon  rode  horse- 
back; William  Cullen  Bryant,  upon  rising  in  the  morning, 
swung  a  chair  around  his  head,  took  wand  exercise  with  a 
cane,  and  practiced  other  gymnastics.  He  walked  five 
miles  to  his  work. 

The  connection  between  body  and  mind  is  readily  illus- 
trated. The  pulse  rate  is  affected  by  every  emotion.  Shame 
causes  the  blood  vessels  of  the  face  to  dilate.  Painful  emo- 
tions excite  the  activity  of  the  lachrymal*  or  tear  glands. 
Joy  increases  ease  of  movement.  If  an  excited  or  angry 
man  who  is  walking  to  and  fro  sits  down,  his  excitement 
decreases.  A  starving  man  and  one  suffering  from  fever 
have  hallucinations.*  The  Romans  had  the  proverb  "  a 
sound  mind  in  a  sound  body."  The  care  of  the  body  for 
the  mental  effect  as  well  as  for  the  sake  of  the  body  itself, 
is  only  gradually  regaining  the  high  place  it  held  among  the 
Greeks  and  the  Romans,  a  place  which  it  lost  during  the 
Dark  Ages.  "  Hysteria  *  and  nervous  exhaustion  are  the 
fruits  not  of  over-work,  but  of  lack  of  varied  and  interesting 
employment.  The  absurd  opinion  that  hard  work  is  menial 
and  low,  leads  to  most  pernicious  consequences.  The  girl 
who,  turning  from  brain  work  to  manual  labor,  can  cook, 
scrub,  wash,  and  garden,  invites  the  bloom  of  health  to  her 
cheeks ;  while  the  fine  do-nothing  lady  loses  her  good  looks, 
suffers  from  the  blues,  and  is  a  nuisance  to  her  friends  and 
a  misery  to  herself." 

The  effect  of  activity  on  the  nervous  system.  —  If  the 
cells  of  any  tissues  are  not  active  in  the  performance  of  the 
work  for  which  they  are  intended,  they  become  weakened. 
It  is  the  same  with  the  nervous  system.  Fresh  and  new 
sensations  are  necessary  for  the  health  of  the  brain;  those 
mental  faculties  that  are  used  become  strong.  Unused 


318  Healthful  Living 

muscles  become  flabby  and  ill-nourished  because  the  circu- 
lation in  them  is  weakened ;  the  circulation  in  inactive 
nervous  tissue  also  becomes  less  active.  Mental  activity 
strengthens  the  nervous  system  and  the  body  in  general. 
If  one  protects  his  sensory  nerves  by  too  warm  clothing  and 
never  lets  the  cold  air  strike  them,  they  become  weakened 
and  unreliable  and  allow  the  blood  vessels  to  lose  tone.  They 
are  likely  to  do  strange  things  with  the  circulation,  causing 
colds  and  disease.  If,  because  of  pulpy  or  soft  food,  the 
nerves  of  the  alimentary  canal  are  not  stimulated  mechan- 
ically, peristalsis  is  weakened  and  the  intestine  becomes 
clogged.  The  loss  of  tone  in  the  circulation  and  the  sluggish 
peristalsis,  with  the  troubles  that  follow,  can  often  be  improved 
by  taking  a  cold  bath  every  morning.  The  stimulus  to  the 
sensory  nerves  spreads  reflexly  to  the  vasomotor  nerves  and 
to  the  autonomic  fibers  of  the  intestine ;  these  are  "  toned 
up  "  and  restore  activity  to  the  involuntary  muscles. 

The  effect  of  sleep. — The  cells  of  the  body  with  all  their  in- 
dustry are  not  tireless,  and  at  intervals  require  rest  (Figs.  183, 
184, 185).  During  sleep  the  heart  beats  more  slowly,  respira- 
tion is  less  rapid,  the  muscles  in  general  are  relaxed,  the  gland 
cells  diminish  their  secretions,  and  digestion  is  slow.  The 
production  of  heat  is  lessened  and  the  body  must  be  pro- 
tected from  cold.  Yet  consciousness  is  the  only  function 
entirely  in  abeyance.  The  sound  of  a  passing  vehicle 
quickens  the  pulse  of  the  sleeper  without  awaking  him;  if 
he  is  touched,  he  moves.  Sleep  is  deepest  during  the  second 
hour,  and  it  then  takes  a  much  louder  sound  to  awaken  him 
than  during  later  hours.  Sleep  becomes  gradually  lighter 
until  awakening  occurs.  When  consciousness  is  partly 
present,  the  condition  is  called  dreaming.*  In  somnambu- 
lism,* the  sleeper  may  talk  or  walk  as  he  dreams. 

There  are  different  explanations  given  for  the  cause  of 
sleep.  Some  believe  that  it  results  from  the  accumulation 
of  waste  products  in  the  body ;  it  is  also  held  that  it  is  due 


Hygiene  of  the  Nervous  System 


V%fehK)-j;:<-/. 
X 


*Sr 


/  .x-v        -.%.-•  '.3  ..:*%:.%.  —  «•  --  ,      —i     „  ••.: 


FIG.  183.  —  Showing  various  types  of  nerve  cells  (bodies)  from  the 
spinal  cord.    These  cells  are  rested. 


320 


Healthful  Living 


to  lack  of  circulation  in  the  brain.  Now  the  process  is  not 
fully  known,  but  it  is  perfectly  clear  that  individuals  re- 
quire sleep  (Figs.  184,  185).  If  sleep  is  interfered  with,  the 
body  is  injured.  There  should  not  be  in  this  as  in  so  many 
other  things  the  disposition  to  make  yourself  and  your  friends 
uncomfortable  by  the  insistence  at  all  times  on  a  certain 
number  of  hours.  There  are  occasions  when  it  may  be  very 


FIG.  184.  —  Tired  nerve  cell  bodies  from  the  spinal  cord.  These  cells 
show  the  nucleus  to  one  side,  the  chromatin  *  decreased  in  amount  and  at 
the  wall  of  the  cell.  Compare  with  the  cells  shown  in  Figs.  183  and  185. 

desirable  to  take  less  sleep  than  customary,  and  we  should 
be  able  to  go  with  less  sleep  for  a  time  in  the  accomplish- 
ment of  important  work.  The  number  of  hours  of  sleep  for 
children  of  different  ages  is  given  on  page  326. 

For  a  sound  nervous  system,  nothing  is  so  indispensable 
as  plenty  of  sound  sleep.  It  is  necessary  for  growth  and  re- 
pair of  the  cells  (Fig.  185).  Infants  sleep  almost  all  the 
time  ;  children  of  four  or  five,  nearly  half  the  time ;  those  of 


Hygiene  of  the  Nervous  System 


321 


ten  or  twelve,  ten  hours;  most  college  students  require 
eight  hours,  and  this  amount  is  required  by  most  adults. 
The  morning  should  bring  a  feeling  of  vigor.  If  we  wake 
tired  and  discouraged,  there  is  something  amiss.  It  may 
be  that  there  was  over-exertion  the  day  before  and  the  sleep 
has  not  been  long  enough,  or  that  we  have  been  up  too  late 
or  have  eaten  improper  things.  If  the  last  is  the  case,  there 
is  apt  to  be  a  bad  taste  in  the  mouth  on  awakening.  By 


FIG.  185.  —  Brain  cells  at  rest,  in  action,  exhausted  (Crile). 

going  to  bed  at  the  same  hour  every  night,  the  habit  is  formed 
of  dropping  off  promptly  and  soundly  to  sleep.  A  cheerful 
state  of  mind  with  resolute  avoidance  of  worry  promotes 
sound  sleep  at  night.  The  sleeping  room  should  be  cool, 
but  it  is  not  necessary  that  water  freeze  "  in  the  pitcher." 
It  should  be  well  ventilated,  the  window  being  left  open 
even  in  moderately  cold  weather  in  the  northern  states,  and 
in  very  cold  weather  in  the  Gulf  states,  unless  the  room  is 
loosely  built. 


322  Healthful  Living 

The  effect  of  fatigue.  —  Waste  products  produced  in  one 
part  of  the  body  are  carried  by  the  circulating  blood,  before 
they  can  be  removed,  to  all  parts  of  the  body.  Fatigue  in 
one  part  causes  a  loss  of  efficiency  in  other  parts.  It  is  well 
known  that  the  boy  who  plays  football  for  two  hours  in  the 
afternoon  is  unable  to  study  in  a  satisfactory  way  in  the 
evening.  Such  fatigue  is  natural  and  healthful.  After 
the  period  of  rest,  the  body  is  recreated  and  the  taking  in 
of  food  by  the  body  cells,  called  assimilation,*  results  in  the 
organization  of  the  food  into  living  tissue.  It  is  known 
that  mental  activity  does  not  greatly  increase  waste  sub- 
stances, but  that  does  not  mean  that  one  cannot  overwork 
mentally.  The  feeling  of  fatigue  which  comes  from  tired 
eye  muscles  and  tired  joints  should  indicate  the  need  for  a 
change  of  activity.  This  change  will  be  satisfied  best  by 
physical  exercise  of  the  game  or  sport  type. 

The  effect  of  alcohol.  —  As  alcohol  acts  on  many  organs 
through  its  action  on  the  nervous  system,  it  would  naturally 
be  supposed  that  the  nervous  matter  itself  would  be  injured, 
and  such  is  the  case  (Figs.  229,  230).  In  fact,  it  is  upon  the 
delicate  nervous  system  that  its  most  destructive  effects  are 
wrought.  One  of  the  first  effects  of  alcohol  is  flushing  of 
the  face  and  a  feeling  of  warmth  on  the  surface  of  the  body. 
This  is  due  to  the  quickened  action  of  the  heart  and  the  dila- 
tion of  the  small  blood  vessels  from  the  effects  of  alcohol 
on  the  nerve  centers  controlling  these  organs.  The  mind  is 
at  first  more  active,  because  the  little  vessels  of  the  brain  are 
dilated  and  blood  is  sent  more  freely  to  that  part.  A  little 
later  the  alcohol  begins  to  disturb  the  reflex  and  coordinating 
powers  of  the  nervous  system,  and  ordinary  muscular  move- 
ments are  performed  imperfectly  and  with  difficulty.  The 
nerve  centers  seem  to  be  attacked  and  paralyzed  progressively 
by  alcohol,  beginning  with  the  highest  and  proceeding  toward 
the  lowest.  The  will  power  and  judgment  first  become 
paralyzed,  and  only  the  emotional  and  impulsive  instincts 


Hygiene  of  the  Nervous  System  323 

of  human  nature  are  left ;  these,  being  no  longer  under  con- 
trol of  reason  and  judgment,  are  likely  to  cause  the  individual 
to  act  in  an  irrational  manner.  In  the  last  stages,  conscious- 
ness and  volition  are  lost,  and  only  that  part  of  the  nervous 
system  in  the  medulla  which  governs  circulation  and  res- 
piration remains  active.  In  other  words,  the  man  is  "  dead 
drunk. "  A  large  quantity  of  alcohol  may  produce  death 
by  paralyzing  even  these  nerve  centers,  thus  stopping  all 
organic  functions.  This  overact  ion  and  irregular  action  of 


Alcohol  and  Precision  as  Shown  by  Marksmanship 

1st  Tests.  No  Alcohol  -Average  No.  of  Hits  23 


2nd  Tests.  Alcohol  Taken  —  Average  No.  of  Hits  3 
3rd  Tests.  No  Alcohol -Average  No.  of  Hits  26 


FIG.  186.  —  Fewer  hits  were  made  on  the  alcohol  days,  but  the  soldiers 
thought  they  were  shooting  better. 

;  » 

the  nerves,  when  repeatedly  occurring,  has  the  effect  finally 
of  deforming  or  destroying  the  nerve  tissue. 

It  is  well  known  that  skill  in  a  movement  or  act  is  de- 
veloped by  a  training  of  the  nervous  system.  Now  alcohol 
lessens  skill  and  precision  in  fine  work.  There  is  no  work 
or  play  that  man  performs  that  cannot  be  performed  better 
without  alcohol.  In  tests  of  target  shooting,  the  advantage 
of  abstinence  and  the  disadvantage  of  using  alcohol  were 
clearly  shown  by  experiment.  In  this  test  (Fig.  186), 
during  the  first  series  no  alcohol  was  used ;  in  the  second 
series  two  thirds  of  a  wine  glass  of  brandy  was  taken  20  to 
30  minutes  before  shooting  and  an  equal  amount  of  alcohol 
in  punch  on  the  evening  before.  No  one  who  aims  to 
achieve  a  place  in  the  world  and  in  the  respect  of  friends 


324  Healthful  Living 

can  afford  to  use  alcohol  in  any  form.  Its  effect  on  the 
nervous  system  is  especially  disastrous. 

Alcohol  lessens  skill  and  precision  in  fine  work  where 
head,  hand,  eye,  muscles,  and  nerves  must  work  together 
for  deftness  and  accuracy. 

It  is  common  knowledge  that  a  musician,  who  is  indulging 
in  alcohol,  will  make  more  mistakes  in  playing.  The 
fine  adjustments  and  coordinations  are  then  no  longer 
possible.  Those  who  look  forward  to  having  power  over 
and  control  of  the  body  should  guard  against  the  danger 
of  alcohol. 

Improper  functioning  of  the  nervous  system.  —  Nearly 
everyone  has  known  of  some  one  who  has  gone  insane.  Such 
disease  of  the  mind  was  little  understood  in  the  past,  and 
insane  persons  were  thought  to  possess  evil  spirits.  In- 
sanity *  is  usually  thought  of  as  coming  quickly,  and  the  most 
fantastic  causes  are  given  for  its  occurrence.  Now  the  im- 
portant thing  for  us  to  remember  is  that  insanity  usually 
develops  slowly  and  its  causes  are  well  known.  Insanity 
is  much  more  frequent  than  is  generally  supposed,  and  in  the 
state  of  New  York  about  one  in  every  200  of  the  adult  popu- 
lation is  in  an  insane  hospital.  In  ten  years  insanity  in  this 
state  has  increased  104  per  cent. 

Drugs  and  insanity.  —  Opium,*  morphine,*  and  cocaine  * 
cause  a  large  proportion  of  the  insane  in  every  state.  Alco- 
holic insanity  may  be  caused  by  the  regular  use  of  alcohol 
even  in  moderate  quantities  which  do  not  produce  intoxica- 
tion. It  is  stated  that  30  per  cent  of  the  men  and  10  per 
cent  of  "the  women  in  the  state  hospitals  are  suffering  from 
conditions  due  to  alcohol.  In  states  where  there  is  pro- 
hibition, the  amount  of  insanity  is  much  less.  This  is 
scientific  information  and  has  the  support  and  belief  of  the 
highest  medical  authorities.  These  poisons,  alcohol,  opium, 
morphine,  and  cocaine  make  up  the  principal  parts  of  many 
patent  medicines.  This  is  another  reason  for  forbidding 


Hygiene  of  the  Nervous  System  325 

their  use  because  they  often  weaken  the  mental  powers 
and  produce  insanity. 

Communicable  diseases  and  insanity.  —  Mental  disturb- 
ance of  a  serious  nature  may  follow  certain  diseases.  The 
poison  from  typhoid  fever,*  diphtheria,*  and  tuberculosis* 
may  so  injure  the  nervous  system  that  complete  recovery 
does  not  occur.  Many  cases  of  insanity  are  produced  by  a 
specific  communicable  disease  that  is  contracted  through 
immoral  acts.  Those  who  are  weak  enough  not  to  con- 
trol themselves  may  look  forward  to  the  possibility  of 
"  softening  of  the  brain/'  or,  as  it  is  called  by  doctors,  general 
paralysis. 

Habits  of  mind  and  insanity.  —  Habits  of  mind  are  im- 
portant factors  in  producing  mental  disturbance.  The 
state  of  mind  that  is  most  favorable  for  the  health  of 
the  nervous  system  is  the  one  in  which  the  individual  is 
satisfied  with  life  and  is  not  nursing  the  misfortunes  that 
happen  to  befall  him.  It  is  dangerous  to  brood  and  pout 
over  slights,  disappointments,  and  injuries.  Such  unwhole- 
some mental  reaction  if  persisted  in  may  tend  toward 
insanity.  Some  people  think  that  their  disposition  is  fixed 
like  the  color  of  the  eye,  but  it  is  not  so.  A  cheerful, 
optimistic,  friendly,  and  happy  disposition  may  be  trained 
and  achieved. 

Hard  work  alone  rarely  causes  a  breakdown  of  the  nervous 
system,  unless  there  is  associated  with  it  loss  of  sleep  and 
worry.  Henry  Ward  Beecher  once  said,  "It  is  not  hard 
work  that  kills  men ;  it  is  worry."  v 

TEN  GOLDEN  RULES  OF  HEALTH  FOR  SCHOOL  CHILDREN  1 

I.  Sleep  —  get  as  many  hours  in  bed  each  night  as  this 
table  indicates  for  your  age.  Keep  windows  in  bedroom 
well  open. 

1  Proposed  by  Dr.  Thomas  D.  Wood,  Columbia  University. 


326 


Healthful  Living 


HOURS  OF  SLEEP  FOR  DIFFERENT  AGES 


AGE 

HOURS  OP  SLEEP 

TIME  IN  BED 

5-6 

13 

6            P.M.  to  7  A.M. 

6-8 

12 

7            P.M.  to  7  A.M. 

8-10 

lit 

7  :  30  P.M.  to  7  A.M. 

10-12 

11 

8             P.M.  to  7  A.M. 

12-14 

10| 

8:30  P.M.  to  7  A.M. 

14-16 

10 

9             P.M.  to  7  A.M. 

16-18 

.    9£ 

9  :  30  P.M.  to  7  A.M. 

II.  Eat  slowly  —  never  between  meals.     Chew  food  thor- 
oughly.    Drink  water  with  meals  but  never  when  there  is 
food  in  the  mouth.    Drink  water  several  times  during  the  day. 

III.  Brush  your  teeth  at  least  once  a  day.     Rinse  mouth 
out  well  with  water  after  each  meal. 

IV.  Be  sure  your  bowels  move  at  least  once  each  day. 

V.  Take  a  warm,  cleansing  bath  with  soap  once  or  twice 
a  week.     Take  a  tepid  or  cool  sponge  (or  shower)  bath  each 
morning  before  breakfast  and  rub -body  to  a  glow  with  a 
rough  towel. 

VI.  Keep  clean  —  body,  clothes,  and  mind.     Wash  your 
hands  always  before  eating. 

VII.  Play  hard  and  fair.     Be  loyal  to  your  team  mates 
and  generous  to  your  opponents. 

VIII.  Study  for  keeps. 

IX.  Do  all  you  can  to  help  keep  your  school  and  your 
home  clean  and  attractive. 

X.  Be  cheerful  and  do  your  best  to  make  the  world  a  better 
place  to  live  in. 

APPLIED   PHYSIOLOGY 
Exercise  I 

1.  Why  is  it  best  to  change  from  very  absorbing  work  to  work 
of  less  interest  a  while  before  retiring? 

2.  Why  is  the  power  of  habit  a  blessing  ?     A  danger  ? 


Hygiene  of  the  Nervous  System  327 

3.  How  does  travel  often  cure  a  sick  person  when  all  else  fails? 

4.  Why  should  we  never  study  immediately  after  eating? 

5.  Is  it  better  for  children  to  play  or  to  take  exercise? 

6.  What  causes  the  peristaltic  action  of  the  stomach? 

7.  Is  one  more  likely  to  sleep  soundly  who  does  his  brain  work 
in  the  forenoon  and  muscular  work  in  the  afternoon  than  if  he 
reverses  the  order? 

8.  How  do  fatigue  and  sleep  affect  the  nervous  system? 

Exercise  II 

9.  How  does  anger  cause  indigestion  ? 

10.  Does  perfectly  comfortable  clothing  from  head  to  foot  con- 
tribute to  one's  ease  in  company? 

11.  Does  uncomfortable  clothing  make  one  self-conscious? 

12.  Is  it  as  important  to  have  the  shoes  and  the  clothing  per- 
fectly comfortable  when  going  out  as  when  staying  at  home  ? 

13.  Would  you  get  more  rest  by  sleeping  for  four  hours  undis- 
turbed, or  by  sleeping  eight  hours  but  being  awakened  every  half 
hour  by  some  noise,  and  going  immediately  to  sleep  again  ? 

14.  When  one  sits  with  the  leg  under  the  body,  why  is  it  that 
the  compression  causes  a  tingling  sensation  or  paralyzed  feeling 
in  the  foot  ? 

15.  Do  the  girl,  who  frets  over  washing  the  dishes,  working 
with  an  unwilling  mind,  and  the  boy  who,  while  he  is  sawing  wood, 
is  wishing  to  go  to  a  baseball  game,  do  their  work  with  more  or 
less  fatigue  than  if  they  worked  cheerfully  and  willingly?     Why? 

16.  What  are  the  causes  of  improper  functioning  of  the  nervous 
system  ? 

Exercise  III 

17.  How  is  a  sneeze  a  protective  act? 

18.  Why  may  a  dyspeptic  digest  a  large  Thanksgiving  or  Christ- 
mas dinner  when  he  often  has  trouble  with  an  ordinary  dinner  ? 

19.  Why  is  it  more  difficult  for  an  adult  to  learn  to  speak  a 
language  than  for  a  child?     Why  do   adults  find  drawing  and 
languages  more  difficult  to  acquire  than  history  and  mathematics  ? 

20.  In  what  two  ways  may  opening  a  window  when  a  student  is 
becoming  dull  and  drowsy  at  his  books  enable  him  to  wake  up  and 
study  with  ease  ? 

21.  Muscles  may  be  classed  as  minor,  such  as  those  of  the  eye, 
voice,  hand;  and  major,  such  as  those  of  upper  arm,  leg,  trunk. 


328 


Healthful  Living 


Why  is  the  use  of  the  minor  muscles  exhausting  to  the  nerves,  while 
the  use  of  the  major  muscles  strengthens  the  nerves? 

22.  Why  do  you  throw  cold  water  upon  a  fainting  person? 

23.  Why  may  cold  feet  cause  sleeplessness  ? 

24.  Why  does  constant  moderate  drinking  undermine  the  health 
more  than  occasional  intoxication  ? 

25.  The  vasomotor  nerves  control  the  size  of  the  blood  vessels. 
Which  nerve  centers  control  these  nerves?     Why  does  a  draught 
blowing  on  the  back  of  the  neck  often  cause  a  cold? 


LABORATORY   EXERCISES 

Reaction  Time.  —  The  nervous  system  is  arranged  to  protect  the 
body  from  injurious  conditions  affecting  it  through  its  environment. 
This  protection  is  shown  when  the  eyes  are  closed  to  shut  out  the 
light  that  is  too  bright,  when  the  hand  is  thrown  in  front  of  the 
face  to  ward  off  a  thrown  missile,  and  when  the  hand  is  withdrawn 


FIG.   187.  —  The  inductorium.     (The  set  screw  holding  the  trunnion 
block  tube  against  the  side  rod  is  not  shown.) 


on  coming  in  contact  with  a  hot  stove.  These  are  a  few  of  the  many 
instances  of  the  protective  reactions  of  the  nervous  system.  Now 
the  quickness  of  this  reaction  varies  in  different  people,  and  the 
length  of  the  time  from  the  moment  the  outside  stimulus  is  received 
and  the  body  reacts  is  shorter  or  longer  depending  on  the  activity 
of  the  nervous  system.  This  time  is  called  the  reaction  time  and 
is  capable  of  measurement. 


Hygiene  of  the  Nervous  System 


329 


Experiment  1.   To  study  the  reaction  time  of  the  nervous  system. 

Material.  —  Inductorium,    signal   magnet,    copper   wires,    elec- 
tric batteries,  kymograph,  and  keys.     (Figs.  187,  188,  189,  190.) 


FIG.  188.  —  Electrodes.     About  two  fifths  the  actual  size, 
electrodes  are  attached  to  the  inductorium. 


The 


Method  and  observation.  —  Arrange  a  signal  in  the  primary  cir- 
cuit of  the  induction  apparatus  with  the  two  keys.  Place  the 
kymograph  with  smoked  paper  in  contact  with  the  recording  point 
of  the  signal  magnet.  Let  the  subject 
hold  the  electrodes  of  the  inductorium 
on  the  tip  of  the  tongue  with  one  hand 
and  with  the  other  hold  down  the  one 
key.  The  experimenter  will  then  spin 
the  drum  and  close  the  other  key. 
This  closing  of  the  key  will  make  the 
circuit  and  hence  will  produce  an 
electric  shock.  When  the  subject  feels 
the  shock  on  the  tongue,  he  breaks  the 
circuit  by  opening  his  key.  This  clos- 
ing and  opening  of  the  circuit  produces  a  movement  of  the  signal 
which  is  recorded  on  the  kymograph,  and  so  there  is  a  graphic 
record  of  the  time  the  stimulus  was  received  and  the  moment  the 
response  was  given.  This  interval  is  the  Reaction  Time. 


FIG.  '189.  —  The  simple 
key ;  about  three  eighths  the 
actual  size. 


FIG.  190.  —  The  signal  magnet. 


33°  Healthful  Living 


GLOSSARY 

Assimilation.  —  The  last  act  of  the  process  of  nutrition.  It  follows 
digestion  and  absorption.  After  the  food  elements  are  di- 
gested and  absorbed,  the  transformation  of  them  into  an  in- 
tegral part  of  the  cells  of  the  body  is  assimilation. 

Chromatin.  —  The  coloring  matter  of  the  nucleus.  The  chromatin 
contains  the  essential  elements  of  the  cell  and  is  important  in 
reproduction  of  the  cell. 

Cocaine.  —  A  white,  bitter,  crystalline  alkaloid  with  the  formula 
(Ci7H2iNO4).  It  produces  loss  of  feeling  when  injected  into 
the  skin. 

Diphtheria.  —  A  disease  caused  by  the  Bacillus  diphtheria.  The 
organisms  grow  on  the  mucous  membrane  of  the  throat, 
larynx,  and  nose  and  produce  toxins  which  circulating  in  the 
blood  cause  the  injury  to  the  heart  and  nerves  and  the  re- 
sulting symptoms. 

Dream.  —  A  succession  of  mental  images,  usually  incoherent  and 
confused,  that  come  in  sleep. 

Fever.  —  A  general  disturbance  of  the  body  characterized  by  an 
increase  in  body  temperature.  Often  preceded  by  a  chill  and 
followed  by  quickened  pulse  and  respiration.  The  communi- 
cable diseases  all  produce  some  fever. 

Hallucination.  —  An  apparent  perception  with  no  corresponding 
external  object.  Sights  seen  and  sounds  heard  without  there 
being  any  object  or  cause  of  sound,  illustrate  the  condition. 

Hysteria.  —  A  nervous  state  in  which  the  individual  rapidly 
changes  from  laughing  to  crying  accompanied  with  a  choking 
sensation  in  the  throat. 

Insanity.  —  A  condition  of  the  mind  brought  about  by  diseased 
processes  in  the  brain  or  nervous  system.  The  individual 
lacks  the  ability  to  think  and  act  in  the  way  which  is  con- 
sidered by  most  people  to  be  sane. 

Lachrymal.  —  The  gland  which  secretes  tears ;  the  duct  which 
carries  them  over  the  eye  ball;  the  name  of  the  secretion 
itself. 

Morphine.  —  A  bitter,  crystalline,  narcotic  alkaloid  with  the 
formula  (CnHigNOs).  It  is  a  derivative  of  opium. 

Opium.  —  A  product  of  the  unripe  capsules  of  the  poppy.  Chemi- 
cally it  is  a  mixture  of  different  alkaloids,  chief  among  them 
being  codein  and  morphine. 


Hygiene  of  the  Nervous  System  331 

Somnambulism.  —  Performing  the  act  of  walking  and  other  pur- 
posive acts  during  sleep. 

Tuberculosis.  —  A  disease  caused  by  the  Bacillus  tuberculosis. 
This  organism  may  attack  almost  any  structure  in  the  body. 
There  may  arise  tuberculosis  of  the  lungs,  of  the  liver,  of  the 
brain,  of  the  kidneys,  of  the  intestines,  and  other  organs. 

Typhoid  fever.  —  A  disease  caused  by  the  Bacillus  typhosus.  This 
organism  attains  entrance  to  the  body  through  water,  milk, 
or  food  that  has  been  contaminated  by  one  sick  with  the 
disease. 


CHAPTER  XVII 
SENSATION   AND    THE    SPECIAL   SENSES 

I.  Classification  of  the  Senses. 

II.  The  Sense  of  Taste. 

III.  The  Sense  of  Smell. 

IV.  The  Sense  of  Sight. 

The  external  parts  of  the  eye 
The  interior  structure  of  the  eye 
The  .act  of  accommodation 

Regulation  by  the  iris  of  the  amount  of  light  admitted 
Defects  of  vision 
Care  of  the  eyes 
V.   The  Sense  of  Hearing. 

Structure  and  function  of  the  ear 
Care  of  the  ear 
VI.    The  Sense  of  Touch. 
Temperature 
Pain 
Pressure 

VII.   The  Muscular  Sense. 
VIII.    General  Sensations. 
Hunger 
Thirst 


Classification  of  the  senses.  —  In  animal  life  the  develop- 
ment of  the  nervous  system  has  produced  certain  groups 
of  nerve  cells  for  the  purpose  of  carrying  on  particular  tasks. 
The  eye  is  a  nerve  structure  which  has  undergone  a  re- 
markable development  so  that  man  may  be  more  familiar 
with  his  environment.  The  endings  of  a  nerve  in  the  tongue 
make  possible  the  distinction  between  sweet  and  sour, 
palatable  and  distasteful  food.  Sensory  nerves  in  the  skin 

332 


Sensation  and  the  Special  Senses 


333 


inform  us  regarding  the  objects  in  the  world  around  us. 
The  touch  sensation  is  compound.  It  conveys  qualities  of 
pressure,  warmth,  cold,  and  pain.  The  temperature  sen- 
sation is  always  projected  externally  to  objects;  the  pain 
sense  goes  inward  and  is  felt  as  a  sensation  *  within  the  body. 
The  sensory  nerves  in  the  skin  have  special  endings  and 
each  nerve  has  special  work  to  do.  There  are  cold  and 
warm,  pressure  and  pain  nerves  and,  when  stimulated,  each 
carries  its  own  kind  of  sensation.  Pressure  nerve  endings 
transmit  a  sense  of  pressure ;  cold  endings  carry  a  sensation 
of  cold,  etc.  Sensory  nerves  also  have  endings  in  the  muscles 
and  these  nerves  on  contraction  of  the  muscle  tell  the  brain 
how  intense  the  contraction  is  and  where  the  part  has  moved. 
Some  of  these  fibers  end  in  the  cerebellum  and  this  sense 
at  work  helps  to  maintain  the  balance  of  the  body.  It  is 
called  our  muscle  sense.  In  addition,  there  are  certain 
common  sensations,  such  as  hunger  and  thirst.  We  feel 
them  as  existing  within  the  body. 


1.  Taste 

2.  Smell 

Special 

3.  Sight 

Senses 

4.  Hearing 

f  Temperature 

5.  Touch  

]  Pain 

6.  Muscle  sense 

I  Pressure 

General 

1.  Hunger 

Senses 

2.  Thirst 

Sensations 


The  sense  of  taste.  —  It  was  mentioned  that  the  tip  of 
the  tongue  has  a  very  keen  sense  of  touch.  The  tongue  is 
a  very  muscular  organ,  and  when  we  are  eating,  it  helps  to 
keep  the  food  between  the  teeth ;  it  also  does  the  chief  part 
of  the  work  in  the  beginning  of  the  process  of  swallowing. 
But  perhaps  its  most  important  function  is  to  afford  a  home 
for  the  nerves  of  taste.  These  nerves  consist  of  a  branch 
of  the  fifth  pair  of  nerves,  which  are  distributed  over  the 


334  Healthful  Living 

front  part  of  the  tongue,  and  the  ninth  pair,  which  go  to 
the  back  part  of  the  tongue  (Fig.  171).  Although  we  often 
speak  of  food  as  being  palatable,  the  sense  of  taste  in  the 
palate  is  very  feebly  developed. 

What  we  call  flavors  affect  us  through  the  sense  of  smell. 
If  the  nostrils  be  held  closed,  a  piece  of  onion  placed  on 
the  tongue  does  not  have  the  "  taste  "  of  onion  at  first, 
nor  at  all,  unless  particles  are  wafted  up  and  pass  through 
the  pharynx  into  the  nose.  An  apple  is,  under  the  same 
conditions,  as  tasteless  as  an  Irish  potato.  If  the  nose  is 
held  shut,  ground  coffee  placed  upon  the  tongue  loses  its 
flavor  and  is  as  tasteless  as  sand,  if  the  tongue  is  wiped  dry. 
The  way  to  make  these  tests  is  to  obtain  the  articles  and 
have  them  given  to  you  for  tasting,  without  knowing  which 
you  are  getting ;  then  find  whether  or  not  you  can  tell  the 
difference. 

Substances,  in  order  to  be  tasted,  must  first  be  dissolved 
on  the  tongue.  The  tip  of  the  tongue  is  most  sensitive  to 
sweets  and  salines,  the  back  part  to  bitters,  and  the  sides  to 
acids. 

The  sense  of  smell.  —  In  quiet  breathing  most  of  the  air 
passes  along  the  lower  parts  of  the  nasal  passages,  just  above 
the  hard  palate.  Fibers  of  the  olfactory  nerve  end  mostly 
in  the  higher  part  of  the  nasal  passages.  When  we  wish  to 
test  an  odor,  we  sniff,  that  is,  we  take  a  sudden  inspiration 
by  jerking  the  diaphragm  down.  A  volume  of  air  larger  than 
usual  rushes  in,  more  of  it  passes  over  the  parts  of  the  walls 
in  which  the  olfactory  fibers  are  located.  It  is  necessary 
that  the  substance  producing  the  odor  be  in  a  very  finely 
divided  condition,  probably  gaseous. 

Smell  has  its  source  in  the  beginnings  of  the  respiratory 
passages,  just  as  taste  is  at  the  gateway  of  the  alimentary 
canal ;  and  just  as  taste  by  its  influence  on  the  salivary  and 
gastric  glands,  greatly  influences  digestion,  so  the  sense  of 
smell  greatly  influences  the  respiratory  acts.  The  breath- 


Sensation  and  the  Special  Senses  335 

ing  of  a  pleasant  odor  increases  the  depth  of  the  breathing. 
Pleasant  odors,  as  of  flowers  and  of  fresh  country  air  and  of 
the  forest,  contribute  to  our  health  and  well-being.  Why 
do  foods  lose  flavor  when  one  has  a  very  bad  cold  in  the 
nose? 

The  sense  of  sight.  —  The  eye  brings  to  the  brain  from  the 
external  world  pictures  of  form,  color,  and  movement.  With- 
out the  eye,  color  and  movement  could  not  be  ascertained 
and  form  would  be  only  partially  sensed.  How  would  form 
be  known  in  part?  This  marvelous  structure,  the  eye,  is 
set  into  a  hollow,  formed  by  the  bones  of  the  skull.  The 
camera  in  structure  and  function  is  similar  to  the  eye. 
Familiarize  yourself  with  the  parts  of  a  camera  and  identify 
these  with  parts  in  the  eye. 

The  external  parts  of  the  eye.  —  The  eye  is  a  globular  organ, 
set  in  a  bony  socket.  It  is  controlled  in  its  movements  by 
muscles,  protected  from  dust  and  dirt  by  the  lids  and  lashes, 
and  on  its  exposed  surface,  the  conjunctiva,  it  is  moistened 
by  a  secretion  from  the  lachrymal  gland.  These  structures 
form  the  external  parts  of  the  eye  and  will  be  described  be- 
fore the  internal  structure  of  the  eye  proper  will  be  given. 

The  Oculo-motor  Muscles  (Fig.  191).  —  The  eyeball  is 
capable  of  being  turned  in  all  directions  by  means  of  six 
slender  muscles  which  begin  in  the  back  part  of  the  orbit. 
Four  of  them  are  straight.  The  one  above  turns  the  eye 
upward,  the  one  below  turns  it  downward,  the  one  toward  the 
nose  turns  it  inward,  and  the  one  toward  the  temple  turns 
it  outward.  The  other  two  are  oblique.  The  superior 
oblique  muscle  passes  forward  through  a  loop  which  serves 
as  a  pulley  near  the  inner  upper  front  part  of  the  orbit 
(Fig.  191).  It  rotates  the  eye  in  one  direction,  and  its  antag- 
onist, the  inferior  oblique  muscle,  rotates  it  in  the  opposite 
direction.  "  Cross  eyes "  are  caused  by  too  great  con- 
traction of  the  internal  straight  muscles,  and  "  wall  eyes  " 
are  caused  by  too  great  contraction  of  the  external  straight 


336 


Healthful  Living 


xe-c,us 


FIG.  191.  —  A,  the  muscles  of  the  right  eye- 
ball (viewed  from  above).  B,  the  muscles  of 
the  left  eyeball  (viewed  from  the  outer  side). 


muscles.     The  defects  may  be  remedied  by  a  skillful  surgeon, 
who  cuts  the  proper  muscle  with  a  suitable  instrument,  and 

permits  it  in  healing 
become   attached 
another      point 

f»         1  1  i  i 

Optic 


to 
to 
farther  back. 

A  person  is  blind 
while  the  eyes  are 
moving.  Watch 
while  some  one  in 
front  of  the  class 
tries  to  move  the 
eyes  gradually  and 
uniformly  across  the 
field  of  vision.  Do 

the  eyes  move   by  jumps   or  steadily?      The   motions   of 

the    lids    and    eyeball    give    the    expression    of    the    eye. 

The  eyeball  itself  has  hardly  more  expression  than  a  glass 

eye. 

We  judge  the  distance  of  objects  by  the  lines  of  conver- 

gence of  the  two  eyes.     This  conver- 

gence is  accomplished  by  the  harmoni- 

ous  action  of   the   eye  muscles.     A 

boy  with   one  eye    has  difficulty  in 

knowing    when    a    ball    thrown    will 

reach  his  hand.     When  we  look  at  a 

solid   object,  each   eye   sees  a   little 

more  of  the  object  on  its  side  than 

does  the  other.     Thus  two  eyes  make 

it  easier  to  distinguish  bodies.     By 

taking    two    photographs    of     a    solid 

scene  from  slightly  different  points 

and  arranging  them  so  that  the  eyes   of  light  from  A  and  B  are 

look  at  the  pictures  separately  &' 


FlG192<_  Diagram  of 

a  stereoscope.    Two  photo- 


the  same  time  the  idea  of  solidity   appear  to  come  from  c. 


Sensation  and  the  Special  Senses  337 

is  given.  The  stereoscope  *  (Fig.  192)  secures  this  arrange- 
ment. 

The  Lids.  —  The  upper  and  lower  lids  protect  the  eye. 
They  are  supplied  with  muscles  and  can  be  moved  very 
quickly.  The  upper  lid  has  greater  movement.  From  the 
edges  of  the  lids  grow  hairs,  called  lashes.  The  lashes  pro- 
tect the  eye  from  dust  and  are  very  sensitive  to  all  pressure. 
The  under  surface  of  the  lids  is  covered  by  conjunctiva  in 
which  are  located  glands  which  produce  an  oily  secretion. 
This  secretion  prevents  the  rapid  drying  of  the  watery  se- 
cretion that  comes  from  the  lachrymal  gland. 

The  Lachrymal  Gland.  —  The  lachrymal  gland  is  some- 
times called  the  tear  gland.  It  is  located  above  the  eye- 
ball, between  the  ball  and  the 
bony  arch  on  the  side  toward 
the  temple.  It  is  flattened  and 
oval  in  shape,  about  three  quar- 
ters of  an  inch  in  length.  About  J)uct' 
ten  small  ducts  lead  from  it  and 
open  on  the  under  side  of  the 
upper  lid.  The  secretion  that  it 

furnishes    to    the    conjunctiva    is    partially  dissected  to  show  lach- 

formed  continually.  The  tears  J^  *^d  and  lachrymal 
pass  across  the  eye  and  flow  into 

two  small  ducts,  the  openings  into  which  can  be  seen  on  the 
borders  of  each  eyelid  near  the  inner  angle  of  the  eye.  They 
open  into  a  canal  which  leads  into  the  nasal  passage  (Fig.  193). 
When  one  weeps,  why  is  it  necessary  to  blow  the  nose  fre- 
quently? At  the  ordinary  rate  of  supply,  the  tears  do  not 
overflow,  as  there  is  a  waxy  secretion  along  the  edge  of  the 
eyelid  that  turns  them  toward  the  ducts.  When  have  you 
noticed  a  waxy  secretion  in  the  corner  of  the  eye? 

The  Conjunctiva.  —  The  eye  is  apparently  set  in  a  slit 
in  the  skin  of  the  face,  but  this  is  not  really  the  case.  The 
skin  of  the  eyelids  turns  inward  over  their  edges  and  becomes 


338  Healthful  Living 

a  thin,  transparent,  and  exceedingly  sensitive  mucous  mem- 
brane, called  the  conjunctiva.  It  is,  like  other  mucous 
membranes,  composed  of  epithelial  cells.  The  conjunctiva 
goes  back  under  the  lid  and  over  half  the  eyeball  itself  to 
the  other  lid,  so  that  the  eye  is  really  behind  the  skin.  When 
the  eye  is  directed  very  much  to  one  side,  the  conjunctiva 
is  sometimes  seen  lying  in  wrinkles.  The  veins  which  we 
think  we  see  in  the  white  wall  of  the  eyeball  when  the  eye 
is  "  blood-shot  "  are  usually  in  the  conjunctiva,  which  is 
so  transparent  that  we  do  not  easily  see  it  unless  its  vessels 
are  swollen.  Trachoma,*  sometimes  known  as  "  sore  eyes," 
is  a  disease  of  the  conjunctiva.  This  serious  infection  of 
the  conjunctiva  is  not  infrequent  among  school  children. 
This  disease  is  very  serious  and  affects  the  sight  if  not 
properly  cared  for.  It  is  transmitted  from  child  to  child 
by  use  of  the  common  roller  towel,  by  borrowed  handker- 
chiefs and  other  personal  property  that  comes  in  contact 
with  the  face  of  the  child.  Always  use  your  own  individual 
towel  and  never  lend  or  borrow  a  handkerchief. 

The  Health  Department  of  the  City  of  New  York  has 
issued  the  following  bulletin  for  parents : 


DEPARTMENT    OF   HEALTH 

THE  CITY  OF  NEW  YORK 
Instructions  to  Parents  Regarding  Trachoma 

Trachoma  is  a  contagious  disease  of  the  eyelids.  If  left  un- 
treated it  is  very  dangerous  to  the  eyesight. 

It  first  attacks  the  inner  surface  of  the  eyelids,  later  it  spreads 
to  the  eyeball  itself  and  causes  loss  of  sight. 

In  the  beginning  the  eyes  may  be  red  and  watery  and  they 
may,  from  time  to  time,  contain  matter,  but  often  for  a  long  time 
there  are  no  symptoms  that  the  person  notices,  and  the  disease  is 
frequently  first  discovered  by  the  doctor.  It  is  very  difficult  to 
cure  trachoma,  and  it  is  the  more  difficult  the  longer  the  disease 
has  lasted.  For  this  reason  trachoma  should  be  detected  as  early 


Sensation  and  the  Special  Senses 


339 


as  possible.  It  is  contagious  when  secretion,  that  is  to  say  "  matter," 
is  present.  This  secretion  is  conveyed  from  the  eye  of  the  person 
affected  to  the  eye  of  the  healthy  person  and  thus  sets  up  the 
disease.  The  secretion  is  for  the  most  part  conveyed  by  means  of 
towels,  washrags,  and  handkerchiefs,  and  persons  with  trachoma 
should  always  be  careful  that  their  towels,  washrags,  and  hand- 
kerchiefs are  used  by  themselves  only.  It  is  not  on  the  street 
that  trachoma  is  transmitted  from  one  person  to  another,  but 
generally  in  the  home,  and  it  is,  therefore,  in  the  home  that  the 
greatest  precautions  should  be  taken. 

Children  who  have  trachoma  are  not  allowed  to  attend  school 
unless  they  are  regularly  treated. 

If  your  child  has  sore  eyes,  take  it  to  your  doctor  or  to  a  Dis- 
pensary *  at  once. 

The  interior  structure  of  the  eye.  —  The  eyeball  (Fig.  194) 
is  a  globular  chamber  filled  with  transparent  fluids.  This 


Irrs 
Ci/iary  Musc/e 


Retina 

Choroief 

'c/erot/c  Coat 


FIG.  194.  —  The  anatomy  of  the  eye. 

chamber  is  divided  into  two  compartments  (Fig.  194)  by  a 
semi-solid  crystalline  *  substance  called  the  lens,*  and  a  mus- 
cular diaphragm  (Fig.  195),  the  iris.  The  wall  of  the  eye 
is  made  of  three  layers  of  tissue,  called  coats  of  the  eye. 

Coats  of  the  Eyeball.  —  The  sclerotic  *  coat  is  the  tough 
white  outer  coat  of  connective  tissue.     It  preserves   the 


34°  Healthful  Living 

shape  of  the  eye  and  serves  for  the  attachment  of  the  muscles. 
This  coat  is  pierced  in  only  one  place,  and  that  is  for  the 
entrance  of  the  optic  nerve.  It  is  continuous  over  the  front 
of  the  eye,  where  it  becomes  transparent,  and  is  called  the 
cornea.  You  can  see  the  cornea  bulging  out  in  the  front, 
of  a  classmate's  eye  if  you  look  at  it  from  the  side.  The 
middle  coat,  the  coat  just  within  the  sclerotic,  is  the  choroid.* 
It  consists  of  pigment  cells  and  blood  vessels.  The  choroid 
coat  does  not  cover  completely  the  whole  ball.  It  is  not  over 
the  cornea,  but  at  the  beginning  of  the  cornea  the  choroid 
turns  toward  the  center  of  the  eye  and  forms  the  iris.  The 
iris  has  an  opening  called  the  pupil,*  and  this  opening  be- 
cause of  small  muscles  can  change  in  size.  The  iris  changes 
the  opening  of  the  pupil  to  allow  just  sufficient  light  to 
properly  stimulate  the  optic  nerves.  When  the  light  is 
dim,  the  pupil  is  opened  wider  and  in  bright  light  it  is  con- 
tracted to  a  small  opening.  The  point  where  the  choroid 
leaves  the  sclerotic  coat  to  form  the  iris  marks  the  attach- 
ment of  the  lens  to  the  choroid.  These  two  structures,  iris 
and  lens,  divide  the 'chamber  of  the  eye  into  two  compart- 
ments. In  the  anterior  chamber  is  the  aqueous  humor;* 
in  the  posterior,  is  the  vitreous  humor.* 

The  retina  *  is  the  third  or  innermost  layer  of  the  wall.  It 
lines  the  chamber.  It  is  composed  of  the  end  filaments  of 
the  optic  nerve.  These  are  a  hundred  thousand  or  more  in 
number.  The  ray  of  light  on  coming  into  the  eye  stimulates 
these  sensory  endings  of  the  optic  nerve.  To  receive  this 
stimulus  of  the  light  ray  is  'the  function  of  the  retina,  and  to 
transmit  it  to  the  brain,  is  the  function  of  the  optic  nerves 
(Fig.  197). 

The  Aqueous  Humor.  —  The  aqueous  humor  is  a  trans- 
parent liquid.  This  liquid  gives  firmness  to  the  front  part 
of  the  eye.  It  allows  rays  of  light  to  pass  through  without 
deflection. 

The  Vitreous  Humor.  —  The  posterior  compartment  is 


Sensation  and  the  Special  Senses  341 

the  larger  and  main  part  of  the  chamber.  The  vitreous 
humor  that  fills  this  space  is  a  perfectly  clear  liquid. 

The  Crystalline  Lens.  —  The  lens  (Fig.  194)  is  a  perfectly 
clear  transparent  structure,  jelly-like  in  consistency.  It  is 
suspended  by  ligaments  from  the  choroid  at  the  place  where 
the  iris  begins.  The  ligament  is  called  the  suspensory 
ligament. 

Take  a  lens  that  is  rounded  outward  (convex)  *  on  both 
sides,  such  as  a  hand  magnifier,  or  even  a  strong  lens  from 
an  old  person's  spectacles.  Hold  this  up  on  the  side  of  a 
room  opposite  to  a  window  and  catch  the  image*  of  the 
window  on  a  white  cardboard  held  back  of  the  lens.  This 
illustrates  how  the  image  of  an  external  object  is  formed  by 
the  crystalline  lens  upon  the  retina.  If  some  one  stands 
up  in  the  window,  does  he  appear  in  the  upper  or  lower  part 
of  the  image?  If  he  moves  to  the  right,  in  what  direction 
does  his  image  move?  The  reversals  are  explained  by  the 
crossing  of  the  rays  of  light  as  they  pass  through  the  lens. 
If  two  lenses  of  different  thickness  be  used,  it  will  be 
found  that  the  cardboard  must  be  moved  close  to  catch 
the  image  from  the  thicker  lens.  The  lens  serves  to 
refract  the  rays  of  light  and  focus  them  to  produce  a  clear 
image. 

The  Yellow  Spot.  —  The  yellow  spot  is  a  minute  area  of 
the  retina  that  is  in  direct  line  from  the  pupil.  The  nerve 
endings  in  this  area  are  of  such  a  character  that  vision  is 
clearest  at  this  point  (Fig.  194). 

The  Blind  Spot.  —  Light  falling  on  the  optic  nerve  itself 
does  not  give  the  sensation  of  light,  but  gives  it  only  when 
falling  upon  the  ends  of  the  nerve  fibers.  Where  the  optic 
nerve  enters  the  eyeball,  there  are  none  of  these  endings, 
and  the  light  that  falls  there  does  not  enable  us  to  see  any- 
thing. In  the  following  experiment  shut  the  right  eye,  and 
be  careful  not  to  let  the  eye.  waver  :  *  Read  this  line  slowly. 
Can  you  see  the  star  all  the  time?  If  not,  change  the  dis- 


342 


Healthful  Living 


tance  to  the  book  and  read  the  line  again.  In  the  human 
eye  the  optic  nerve  enters  not  in  the  center,  but  at  a  point 
toward  the  other  eye.  The  optic  nerve  along  its  course  is 
not  sensible  to  light,  but  if  it  is  cut,  it  gives  the  sensation  of 
a  flashlight.  This  shows  that  the  nerve,  when  stimulated, 
responds  by  transmitting  the  kind  of  impulse  that  is  as- 
sociated with  its  function. 

The  act  of  accommodation.  —  Hold  a  pencil  or  finger  in 
line  with  some  object,  as  a  picture  on  the  wall.  When 
looking  at  the  finger,  the  picture  is  blurred  and  vice  versa. 


FIG.  195.  —  Diagram  to  illustrate  accommodation. 

When  looking  up  from  a  book  that  we  are  reading,  to  a 
distant  object,  we  do  not  realize  that  any  change  in  the 
eye  is  necessary;  but  the  lens  changes  in  shape,  becoming 
more  flattened  for  the  more  distant  object,  and  becoming 
thicker  again  when  a  near  object  is  looked  at,  thus  always 
bringing  the  rays  to  a  focus  upon  the  retina  at  whatever 
distance  the  object  may  be  (Fig.  195).  But  the  power  fails 
at  a  point  called  the  near  point,  about  four  inches  from  the 
eye  for  most  persons,  and  the  image  becomes  indistinct. 
The  change  in  shape  of  the  lens  is  called  accommodation ; 
it  is  brought  about  by  means  of  the  muscular  fibers  around 
the  lens.  Straining  of  the  muscles  is  required  for  looking 
at  very  near  objects. 


Sensation  and  the  Special  Senses  343 

Regulation  by  the  iris  of  the  amount  of  light  admitted.  — • 
Look  toward  a  bright  window  or  the  sky  and  note  by  means 
of  a  hand  mirror  the  size  of  the  pupil.  Turn  at  right  angles 
to  the  light,  still  looking  in  the  mirror,  and  note  the  size 
of  the  pupils.  What  have  you 
noticed  about  the  eyes  of  a  cat  at 
night  or  in  the  darkened  room? 
How  do  your  own  eyes  feel  when 
going  from  the  dark  into  a  lighted 
room  ?  Can  you  see  as  well  when 
you  first  go  from  a  brightly  *he  retina  at  B- 
lighted  room  into  a  dimly  lighted 

one,  as  after  being  in  the  dim      

light  for  a  short  time  ?     The  iris 
contains   circular   muscle  fibers,    A 
which    reduce    the    size    of    the 

•  i  t          i-     . .         /»!  i  •    i          Myopic,   or    nearsighted     eve,   in 

pupil,  and  radiating  fibers,  which  which  „„„,!,,,  raya  of  light  (A,  A) 
enlarge  the  pupil.  The  arrange-  '--  £™ '.- l™^  ££"» 

ment   Of    pigment   Sometimes    fol-    the  retina  at  B,  the  rays  diverging 

lows  the  line  of  the  fibers.  Have 
you  ever  noticed  lines  in  the  iris  ? 
Did  you  ever  whirl  a  stick 
with  a  glowing  coal  on  its  end  ? 
What  was  noticed?  Can  you 
notice  anything  similar  if  vou 

*  °  Hypermetropic,  or  farsighted,  eye, 

shake   the   hand   up   and   down  in  which  parallel  rays  of  light  (A,  A) 

.    ,  ,       ,      ,,  .,        ,,          r,       -re  are  focused  behind  the  retina  at  D, 

quickly  before  the  face  ?       If  yOU    producing  a  blurred  image  at  B. 

gaze  for  a  moment  at  a  bright  FIG.  196. 

light,  then  quickly  close  the  eyes, 

what  is  noticed  after  the  eyes  are  closed?  These  effects, 
called  after-images,*  are  produced  by  the  action  of  light 
upon  the  pigment  of  the  retina,  an  effect  which  persists 
for  a  fraction  of  a  second  after  the  light  is  removed. 

Defects  of  vision  (Figs.  196,  198).  —  In  near-sighted  eyes  the 
eye  is  too  long  from  front  to  back,  and  the  rays  come  to  a 


344 


Healthful  Living 


focus  before  reaching  the  retina.  Among  savage  nations, 
where  no  books  are  used,  almost  every  one  has  good  sight, 
and  nearsightedness  is  hardly  known.  Nearsightedness  may 
be  inherited  or  may  begin  with  children  at  school.  Some 
children  seem  to  have  a  natural  wish  to  get  their  eyes  close 
to  the  book  or  writing.  This  is 
very  undesirable  for  nearsighted 
persons.  The  head  should  be  held 
erect  in  reading,  to  prevent  blood 
congesting  in  the  eyes,  and  to  pre- 
vent round  shoulders  and  flat  chest. 
The  proper  distance  for  reading  is 
fourteen  to  eighteen  inches.  The 
farsightedness  that  occurs  in  youth 
is  caused  by  the  eyeball  being  too 
flat.  In  the  farsightedness  of  old 
age  the  lens  has  also  lost  its  elas- 
ticity, so  that  its  shape  cannot  be 
sufficiently  changed  to  bring  the 
lights  from  near  objects  to  a  focus 
on  the  retina.  In  farsightedness, 
convex  glasses  are  used,  and  in 
nearsightedness,  concave  glasses 
are  used.  Astigmatism  *  is  a 
defect  caused  by  unequal  curva- 
ture of  the  cornea  in  different 
directions. 

Care  of  the  eyes.  —  Sight  is  priceless.  (When  reading  is 
mentioned  in  these  suggestions,  it  is  meant  to  include  such 
work  as  writing,  sewing,  embroidering,  etc.) 

1.  It  is  important  to  have  proper  light.  The  light  should 
be  steady,  not  flickering;  we  should  not  read  after  sunset 
by  the  fading  twilight ;  we  should  not  read  with  the  sunlight 
falling  on  the  book;  we  should  not  read  facing  a  window 
or  with  a  light  directly  in  front,  unless  the  eyes  are  protected 


FIG.  197. —  Diagram  of 
the  course  of  the  retinal 
nerve  fibers.  Light  from  A 
strikes  the  outer  part  of  the 
right,  and  the  inner  part  of 
the  left,  retina.  The  fibers 
from  these  parts  go  to  the 
right  half  of  the  brain,  B. 
N  represents  the  nose.  The 
spots  A  and  A  on  the  retinae 
are  habitually  stimulated 
together. 


Sensation  and  the  Special  Senses 


345 


346 


Healthful  Limng 


by  a  shade.  The  best  artificial  light  is  that  given  in  the 
indirect  or  semi-indirect  *  method  of  illumination,  either  by 
gas  or  electricity  (Fig.  199).  In  such  lighting  there  is  no 
glare.  Is  there  glare  on  the  blackboard  in  your  room? 


FIG.  199.  —  Indirect  lighting  without  glare. 

This  means  that  the  windows  are  not  placed  properly. 
Light  curtains  diffuse  the  light  evenly,  but  dark  curtains 
cause  lights  and  shadows. 

2.  The  state  of  the  eyes  is  of  importance.  We  should  not 
read  when  tired  or  sleepy;  when  convalescing  from  an  ill- 
ness ;  with  the  head  bent  down ;  when  the  eyes  are  sore ; 
when  they  are  tired,  unless  we  rest  them  every  few  minutes 
by  looking  at  far  objects:  when  riding  in  jolting  cars  and 
carriages ;  when  the  circulation  is  impeded  by  tight  clothing 
around  the  neck. 

"  Tobacco  blindness  "  sometimes  results  from  smoking. 


Sensation  and  the  Special  Senses 


347 


The  first  symptom  is  color  blindness,  which  is  followed  by 
haziness  of  vision,  and  finally,  by  partial  or  complete  loss 
of  sight. 

3.  The  character  of  the  object  of  vision  is  of  importance. 
The  type  from  which  books  are  printed  should  be  large. 
The  paper  should  not  be  pure  white  or  glazed,  but  a  neutral 
tint ;  it  should  be  opaque,  so  that  the  printing  will  not  show 
through  from  the  reverse  page ;  the  lines  should  not  be  more 
than  four  and  a  half  inches  long.  Publishers  of  magazines 
are  the  worst  offenders  in  using  shiny  glazed  paper  because 
it  brings  out  the  beauty  of  fine  engravings. 

The  sense  of  hearing.  —  The  ear  brings  to  the  auditory 
area  of  the  brain  sensations  derived  from  sound.  These 
sensations  are  received  and  transmitted  by  the  auditory 
nerve.  For,  the  purpose  of  receiving  it  has  a  special  sense 
organ,  the  ear. 

Structure  and  function  of  the  ear.  —  The  ear  may  be  de- 
scribed in  three  parts,  the  outer,  middle,  and  inner  ear 


Auditory 
Nerve 


Semi-  Cir  cula 
C 'a nets 


Middle  Ear 
with  Bones 


FIG.  200.  —  Diagram  of  ear  and  Eustachian  tube. 

(Fig.  200).  The  outer  ear  consists  of  the  cartilaginous 
concha,  the  part  that  is  usually  spoken  of  as  the  "  ear," 
and  the  meatus,  the  canal  leading  into  the  head  from  the 
lower  part  of  the  concha.  Which  part  of  the  concha  is  not 


348  Healthful  Living 

cartilaginous  but  fatty  tissue  ?  Part  of  the  wall  of  the  meatus 
is  of  cartilage,  but  the  deeper  part  has  a  wall  of  bone.  The 
entrance  of  the  meatus  is  guarded  by  hairs,  and  its  wall  is 
covered  with  a  bitter  wax  secreted  by  glands  in  the  lining. 
Its  inner  end  is  closed  by  the  tympanic  membrane,  which 
is  sometimes  called  the  drum,  but  it  is  only  a  drum  skin. 
Three  little  bones  stretch  across  the  true  drum,  which  is 
the  middle  ear,  to  a  small  film  separating  the  middle  ear 
from  the  internal  ear.  These  three  little  bones  are  called 
the  hammer,  anvil,  and  stirrup.  The  middle  ear  communi- 
cates with  the  pharynx  by  a  narrow  tube  called  the  Eusta- 
chian  tube.  This  tube  is  for  the  purpose  of  admitting  air 
to  the  middle  ear,  so  as  to  equalize  the  air  pressure  on  each 
side  of  the  membrane  and  prevent  straining  it.  Sometimes 
blowing  the  nose  may  press  the  air  up  into  the  middle  ear 
and  press  the  walls  of  the  Eustachian  tube  together  and 
close  it.  This  causes  slight  deafness  for  the  time.  The 
pressure  may  be  relieved  by  holding  the  nose  closed  and 
swallowing,  thus  opening  the  passage  to  the  middle  ear. 
One  end  of  the  hammer  is  attached  to  the  inner  surface  of 
the  drum  skin ;  the  other  end  is  attached  to  the  anvil ;  and 
one  prong  of  the  anvil  is  attached  to  the  stirrup,  which  in 
turn  is  fastened  by  base  to  the  small  film  stretched  across 
the  round  hole  in  the  bone,  opening  into  the  inner  ear,  or 
labyrinth.  The  inner  ear  consists  of  several  cavities  con- 
taining a  liquid  in  which  rest  the  endings  of  the  auditory 
nerve.  The  endings  of  the  nerve  are  elaborated  into  an 
organ,  the  cochlea,  for  receiving  sound  waves  and  three 
semi-circular  canals  which  are  concerned  in  equilibrium.* 

Soimd  waves,  entering  by  the  meatus,  set  the  drum  skin 
to  shaking;  the  vibrations  are  conveyed  by  the  chain  of 
bones  (Fig.  201)  across  the  middle  ear  to  the  liquid  of  the 
inner  ear.  The  wave  travels  through  air  in  the  outer  ear, 
solids  in  the  middle  ear,  and  liquids  in  the  inner  ear.  The 
vibrations  of  the  liquid,  in  the  cochlea,  start  nerve  impulses 


Sensation  and  the  Special  Senses 


349 


FIG.  201.  —  Bones  of  right  ear,  enlarged  ; 
malleus,  incus,  and  stapes. 


in  the  fibers  of  the  auditory  nerve,  and  when  these  impulses 

are  received  and  interpreted  in  the  brain,  the  miracle  of  the 

conversion    of    the 

external  sound  wave  ~^     /ncus 

into  the  sensation  of 

sound  is  complete. 

It  is  now  believed 
that  the  semi-cir- 
cular canals  (Fig. 
202)  of  the  inner  ear 
are  not  concerned 
in  hearing.  The 
weight  of  the  liquid 
they  contain  press- 
ing upon  the  nerve  fibers  located  in  them  and  exerting  a 
varying  pressure  according  to  the  position  of  the  body,  gives 
us  the  "  equilibrium  sense,"  which  enables  us  to  know  the 
position  of  the  body  at  all  times,  that  we  may  preserve  its 
equilibrium.  Sight  and  the  muscular  sense  also  contribute 
to  maintain  the  equilibrium. 

Care  of  the  ear.  —  The  meatus  is  self-cleansing ;  the  wax 
changes  into  dry  scales,  which  fall  out.  The  external  ear 
should  be  washed,  but  when  we  reach  the  passage,  we  should 

go  no  deeper  than 
we  can  easily 
reach  with  the 
tip  of  the  finger 
covered  with  a 
damp  cloth ;  es- 
pecially the  finger 
should  not  be 
forced  into  the 

tender  ears  of  children.  A  blow  with  the  flat  hand  upon  the  ear 
may  force  the  air  in  and  injure  the  tympanum.  Picking  the 
ear  with  hard  or  sharp  objects  is  dangerous  to  the  tymimnum. 


Vestibule 


Sem/'-C/rcif/ar 
Cana/s 


Coch/ea 


FIG.  202.  —  The  inner  ear,  or  labyrinth. 


35° 


Healthful  Living 


Sometimes  the  wax  collects  in  a  lump  near  the  drum, 
causing  deafness.  The  remedy  is  to  syringe  the  meat  us 
with  warm  water  until  the  lump  is  softened  and  comes  away. 
The  bitter  wax  is  a  protection  against  insects.  Quinine 
often  interferes  for  a  time  with  the  hearing.  Chronic  cold 
in  the  throat  reaching  the  ear  through  the  Eustachian  tube 
sometimes  injures  the  hearing. 

The  sense  of  touch.  —  The  four  special  senses  of  sight, 
sound,  smell,  and  taste  are  located  in  special  organs.  Touch 

is  located  in  all  parts  of 
the  body.  When  an 
object  touches  the  skin, 
an  impulse  is  taken  to 
the  brain.  There  it  gives 


„ 

FIG.  203.  —  Four  papillse  of  the  true 
skin,  magnified.  The  epidermis  has 
been  removed.  Most  papillae  contain 
touch  corpuscles. 


touch    (Fig.    203),    com- 
posed      of      temperature 

*; 

(warmth     Or    cold),     pain, 

Qr  pressure.      Three  kinds 

r 

of  sensations  are  thus  in- 
cluded in  the  general  name  of  touch.  Touch  strictly  gives 
only  such  ideas  as  those  of  size,  shape,  location,  smooth- 
ness, hardness,  and  dampness.  The  ends  of  the  fingers  can 
distinguish  two  points  as  separate  points  if  they  are  only  -^ 
of  an  inch  apart,  while  if  the-  two  points  are  applied  to  the 
back,  they  feel  as  if  they  were  one  point  until  they  are 
separated  two  inches. 

The  covering  of  epidermis  not  only  protects  the  nerves 
and  the  other  delicate  organs  in  the  true  skin,  from  injury, 
but  also  modifies  any  impression,  so  that  in  producing  a 
sensation  it  is  spread  over  several  nerve  endings  instead  of 
one,  and  is  thus  turned  into  a  gentle  instead  of  a  painful 
sensation. 

Temperature.  —  Temperature  may  give  warmth  or  cold 
sensations.  This  part  of  the  sense  of  touch  is  located  only 


Sensation  and  the  Special  Senses 


in  certain  points  or  spots,  called  heat  spots  and  cold  spots, 
situated  a  small  fraction  of  an  inch  apart  (Fig.  204).  Some 
spots  give  a  sensation  of  heat 
only,  and  some  of  cold  only. 
The  sense  is  so  delicate  that  a 
difference  of  -J-  of  a  degree  of 
temperature  between  two  ob- 
jects can  be  detected.  Ex- 
tremely hot  and  cold  objects 
injure  the  cells  and  do  not 
give  sensations  of  temperature 
but  only  of  pain. 

Pain.  —  A  sensation  greatly 
increased  or  often  repeated  be- 
comes unpleasant  and  is  called 
pain.  The  same  physical  in- 
fluence may  be  felt  at  one 
time  as  a  pleasant  touch,  and 
at  another  time  as  a  pain, 
depending  upon  the  state  of 
the  nerve  tissue.  When  an 
influence  is  becoming  strong  enough  to  endanger  the  body, 
the  simple  sensation  of  touch  becomes  changed  into  one 
of  pain  and  warns  us  to  avoid  the  danger.  When  a  nerve 
is  laid  bare  and  touched,  or  cut  midway  in  its  course,  the 
feeling  is  not  one  of  touch,  but  of  pain.  Pain  is  a  protec- 
tion, and  therefore  more  of  a  good  than  an  evil.  In  many 
diseases  it  is  a  prominent  symptom,  and  the  physician  is 
begged  to  give  relief.  But  the  wise  physician  hesitates 
before  giving  morphine  or  other  sedatives,  knowing  that  to 
drown  the  pain  is  to  conceal  the  danger,  and  take  away  his 
best  evidence  as  to  the  state  of  this  disease.  At  the  same 
time,  he  runs  a  risk  of  starting  a  habit  in  the  patient  of 
deadening  pain  and  hiding  unpleasant  feelings  by  taking 
narcotics,  a  habit  that  may  become  fastened  upon  the 


FIG.  204.  —  Cutaneous  "cold" 
spots  (light  shading)  and  "hot" 
spots  (dark  shading)  ;  anterior 
surface  of  the  thigh. 


352  Healthful  Living 

patient  and  ruin  his  life.  Hence  when  sick  we  should  bear 
pain  bravely. 

Usually  pain  arising  from  the  skin  is  located  definitely  by 
the  nervous  sj^stem  and  the  place  is  easily  recognized.  Pain 
arising  from  an  internal  organ  is  located  very  inaccurately, 
For  example,  the  pain  from  a  severe  toothache  may  be  felt 
quite  generally  over  the  side  of  the  face.  Often  the  pain 
from  an  internal  organ  is  felt  in  a  definite  skin  area  and  so 
cutaneous  pain  in  certain  places  refers  to  trouble  in  cer- 
tain internal  organs.  For  example,  pains  arising  from  the 
stomach  are  located  in  the  skin  at  the  tip  of  the  sternum; 
pains  from  the  heart  in  the  region  of  the  scapula. 

Pressure.  —  The  sense  of  pressure  is  a  part  of  the  touch 
complex.  The  pressure  points  in  the  skin  are  more  numer- 
ous than  the  temperature  points  and  in  the  parts  of  the  body 
supplied  by  hairs  these  pressure  points  lie  over  the  hair 
follicles.  This  explains  the  delicate  mechanism  provided 
in  animals  which  can  feel  their  way  in  the  dark  by  the  long 
hairs  of  the  face.  What  animals  show  such  provision?  It 
has  been  found  that  after  anesthetization  of  an  area  of  the 
skin,  there  remains  a  deep  or  subcutaneous  sensibility  to 
pressure  and  movement.  The  nerves  that  enable  us  to 
distinguish  lighter  pressures  are  associated  with  the  recog- 
nition of  temperatures. 

The  muscular  sense.  —  When  an  object  is  lifted,  it  is 
felt  to  be  distinctly  heavier  if  its  weight  is  increased  by  only 
•j^,  but  when  it  is  laid  upon  the  skin,  its  weight  must  be 
increased  by  £  before  it  feels  heavier.  Hence  it  is  con- 
cluded that  sensations  of  weight  and  resistance  to  the  muscles 
depend  upon  the  amount  of  muscular  effort  needed  to  over- 
come the  resistance  as  well  as  upon  the  feelings  of  pressure 
upon  the  skin  and  body.  Close  your  eyes  and  place  the  in- 
dex finger  of  your  right  hand  on  your  left  eye.  Are  you 
able  to  do  this?  Sensations  coming  from  the  muscles  of 
your  arm,  from  the  tissues  of  the  joints  of  the  arm,  go  to  the 


Sensation  and  the  Special  Senses  353 

brain  and  tell  how  to  direct  the  hand.  This  sense  is  called 
the  muscle  sense.  It  is  of  great  service  in  maintaining  the 
balance  in  walking  and  in  making  coordinations. 

General  sensations  of  the  body.  —  We  have  besides  the 
special  senses,  the  general  sensations  of  hunger  and  thirst. 
These  two  bodily  sensations  arise  from  conditions  within 
the  body  due  to  the  chemical  reactions  or  water  content  of 
the  tissues. 

Hunger.  —  The  sensation  of  hunger  is  due  to  the  con- 
tractions of  the  empty  stomach.  It  has  been  stated  in  the 
past  that  hunger  was  due  to  a  general  need  of  the  body  for 
food,  but  the  sensation  passes  away  long  before  there  is 
time  for  digestion  and  absorption  to  occur.  In  addition, 
hunger  may  be  appeased  by  taking  only  a  small  amount  of 
food.  That  contraction  of  the  empty  stomach  produces 
the  sensation  of  hunger  has  been  experimentally  demon- 
strated by  Dr.  Cannon  of  Harvard,  and  others  have  seen 
by  an  opening  in  the  abdomen  so  that  the  stomach  could 
be  observed,  that  the  stomach  is  contracted  during  the  time 
that  the  sensation  of  hunger  persists.  Eating  between  meals 
keeps  the  stomach  working  so  that  at  mealtime  it  is  not 
contracted  and  ready  to  digest  the  food.  This  is  an  im- 
portant reason  for  not  eating  between  meals.  The  contracted 
state  is  an  expression  of  its  readiness  to  receive  food  and  care 
should  be  taken,  therefore,  not  to  have  habits  that  produce 
a  relaxed  stomach. 

Thirst.  —  The  sensation  of  thirst  is  felt  in  the  pharynx  and 
the  nerves  in  this  region  have  the  power  of  giving  this  sensa- 
tion. It  has  been  learned  that  the  cells  of  the  body  are 
made  of  protoplasm  and  that  this  protoplasm  is  liquid.  We 
also  remember  that  the  cells  are  bathed  in  lymph.  The 
fluid  content  of  the  body  in  health  remains  nearly  constant. 
When  we  sweat,  water  is  lost  and  we  replenish  that  removed 
by  drinking  more  water.  When  the  water  content  falls 
below  a  certain  point  the  nerves  in  the  mucous  membrane 

2A 


354 


Healthful  Living 


of  the  pharynx  are  stimulated  by  the  blood,  which  has  lost 
the  water.     This  gives  us  the  sensation  of  thirst. 


APPLIED   PHYSIOLOGY 


LABORATORY  EXERCISES 

Experiment  1.    To  study  the  sense  of  sight. 

Material.  —  Snellen  Test  Chart   (Plate  X,  back  inside  cover), 
and  figure  for  testing  astigmatism .  (Fig.  205). 


Method  and  Observation. 
20  feet  from  the  observer. 


—  Place  the  Snellen  chart  a  distance  of 
Have  it  placed  at  the  level  of  the  eyes 
and  in  good  light.  The  distance  20 
feet  is  chosen,  because  at  that  distance 
light  comes  into  the  eyes  in  parallel 
rays. 

Hold  a  book  in  front  of  one  eye  and 
have  the  observer  read  the  line  marked 
20  feet.  If  he  can  read  the  letters 
correctly,  the  vision  in  that  eye  is 
normal.  If  he  can  read  only  the 
"40  feet"  line,  the  vision  is  \. 

Test  the  other  eye  in  similar 
fashion. 

The  test  for  astigmatism  is  made  by 
seeing  at  20  feet  if  all  the  lines  of  the 
chart  (Fig.  205)  are  of  equal  width. 
Some  of  the  lines  may  appear  heavier 
or  more  distinct  than  others. 
Experiment  2.  —  To  study  the  sense  of  hearing. 

Method  and  Observation.  —  At  a  distance  of  20  feet  have  the 
observer  stand  with  one  hand  over  one  ear.  At  that  distance, 
whisper  in  a  low  voice  and  test  whether  or  not  the  observer  hears 
and  understands.  The  whispered  voice  will  be  heard  at  20  feet 
by  the  normal  ear. 

In  similar  fashion,  test  the  other  ear. 
Experiment  3.    To  test  color  blindness. 

Material.  —  A  set  of  standard  color  worsteds  with  their  tints 
and  shades. 

Method  and  Observation.  —  Test  the  student  with  the  different 
colors  anci  note  the  difference  in  accuracy, 


FIG.  205.  —  Test  for  astig- 
matism. Reading  distance. 
If  this  defect  exists,  the  lines 
that  run  in  one  direction  will 
appear  more  distinct  than  the 
lines  in  other  directions. 


Sensation  and  the  Special  Senses  355 

Experiment  4.    To  analyze  sunlight. 

Material.  —  Prism. 

Method  and  Observation.  —  Throw  the  rays  of  the  sun  after 
passing  through  the  prism  upon  a  sheet  of  paper.     Note  what 
colors  are  present  in  the  spectrum. 
Experiment  5.    To  test  sharpness  of  vision. 

Material.  —  White  thread  and  black  card. 

Method  and  Observation.  —  Cover  one  eye  and  measure  the 
greatest  distance  at  which  the  thread  can  be  seen  on  the  card. 
Test  each  eye.  Test  both  eyes. 

Determine  the  greatest  distance  when  the  card  is  placed  30  and 
60  degrees  from  the  line  of  vision. 
Experiment  6.    To  test  change  in  iris. 

Material.  —  Two  persons. 

Method  and  Observation.  —  Place  subject  facing  window.  Cover 
one  eye  and  on  raising  the  hand,  note  the  change  in  size  of  the  pupil. 

Compare  size  of  pupil  when  looking  at  near  and  at  distant  objects. 
Experiment  7.  To  test  the  dermal  senses.  (Fig.  204.) 

Material.  —  Drawing  compass,  scale  graduated  to  millimeters, 
fine  horsehair,  pencil,  forceps,  vessels  of  cold,  lukewarm,  and  hot 
water. 

Method  and  Observation.  —  (1)  Place  a  straight  piece  of  horse- 
hair in  forceps  and  determine  the  greatest  length  that  will  give 
sensation  of  pressure.  Then  test  the  relative  sensitiveness  of  the 
palm  and  back  of  the  hand,  the  cheek  and  lips,  forearm  and  fore- 
head. 

(2)  Determine  the  least  that  the  points  of  the  compass  may  be 
separated  and  still  be  recognized  as  two  points,  when  placed  in 
contact  with  the  parts  given  in  (1). 

(3)  Make  slight  pressure  on  the  back  of  the  hand  with  pencil 
and  determine  the  sensations  that  arise. 

(4)  Put  finger  of  right  hand  into  a  vessel  of  warm  water  and 
finger  of  left  hand  into  a  vessel  of  cold  water.     Notice  the  kind  of 
sensations  that  come  from  the  two  fingers.      Does  this  sensation 
change  while  the  fingers  are  kept  in  the  water? 

Withdraw   both  fingers  and  place  them  at  once  into  a  vessel 
of  lukewarm  water.     What  are  the  sensations  experienced  now? 
Experiment  8.    To  test  the  sense  of  taste. 

Material.  —  Salt,  sugar,  vinegar,  quinine. 

Method  and  Observation.  —  Test  with  the  different  substances 
the  tip,  the  sides,  the  back  of  the  dry  tongue  and  determine  where 
the  sense  of  taste  for  the  different  substances  is  located. 


356  Healthful  Living 


GLOSSARY 

After-image.  —  The  sensation  of  an  object  after  the  object  ceases 
to  be  present. 

Aqueous  humor.  —  The  water-like  liquid  in  the  front  chamber  of 
the  eyeball. 

Astigmatism.  —  A  condition  of  sight  in  which  the  light  rays  which 
come  into  the  eye  on  the  horizontal  plane  of  the  eyeball  come 
to  a  different  focus  than  the  rays  that  come  in  over  the  ver- 
tical plane.  It  is  due  to  a  difference  in  the  curvature  of  the 
surface  of  the  cornea. 

Choroid.  —  The  middle  layer  of  the  eyeball.  In  this  layer  are  the 
blood  vessels  that  supply  the  eye. 

Convex-lens.  —  A  lens  that  is  curved  like  the  surface  of  a  sphere. 

Crystalline.  —  Like  a  crystal,  transparent,  clear. 

Dispensary.  —  An  institution  at  which  sickness  is  treated  and  medi- 
cines given. 

Equilibrium.  —  A  state  of  control  of  the  body ;  balance. 

Image.  —  A  visible  representation  of  a  thing. 

Lens.  —  A  structure  capable  of  directing  rays  of  light.  This 
may  be  reflection  to  bring  them  to  a  point  (as  a  sun  mirror) 
or  to  scatter  them. 

Perception.  —  Understanding  of  the  sensation  that  is  received. 

Pupil.  —  The  opening  in  the  center  of  the  eye  caused  by  the  arrange- 
ment of  the  iris  muscle.  This  muscle  has  a  circular  and  radial 
arrangement  and  can  constrict  or  dilate  the  pupil. 

Retina.  —  The  innermost  layer  of  the  eyeball.  It  is  formed  by 
the  branching  endings  of  the  optic  nerve. 

Sclera.  —  The  outermost  layer  of  the  eyeball.  It  is  formed  of  con- 
nective tissue  and  provides  the  eye  with  a  firm  capsule. 

Semi-indirect.  —  A  variety  of  illumination.  In  this  variety  the 
light  units  are  suspended  in  a  bowl-shaped  structure  from  the 
ceiling  and  rays  of  light  are  reflected  downward  from  the  ceil- 
ing and  also  pass  directly  through  the  bowl. 

Sensation.  —  A  conscious  state  resulting  from  a  stimulus. 

Stereoscope.  —  An  optical  instrument  for  blending  into  one  image 
two  pictures  of  an  object. 

Trachoma.  —  A  very  contagious  disease  of  the  eye.  It  is  commonly 
called  "  sore  eyes." 

Vitreous  humor.  —  The  glass-like  liquid  in  the  back  chamber  of 
the  eyeball. 


CHAPTER  XVIII 
SOME   SPECIAL  REGULATIVE  PROCESSES 

I.    The  Regulation  of  the  Temperature  of  the  Body. 
II.    The  Regulation  of  Body  Activity  and  Growth. 
Thyroid  secretion 
Thymus  secretion 
Adrenal  secretion 
Pituitary  secretion 
Pancreatic  secretion 
III.   The  Control  of  the  Voice. 
The  breath 
The  larynx 

The  resonant  chambers 
Pitch,  volume,  and  quality 
The  care  and  culture  of  the  voice 


The  regulation  of  the  temperature  of  the  body.  —  Man 

lives  in  the  torrid  zone  and  in  the  frigid  zone,  yet  his  tempera- 
ture remains  the  same  as  he  goes  from  one  zone  to  another, 
and  as  summer  changes  to  winter.  The  temperature  of  the 
healthy  body  is  about  98.6°  F.  This  is  unmistakable  evi- 
dence that  some  means  of  maintaining  a  uniform  temperature 
exists  in  his  body.  This  means  for  regulation  of  heat  works 
in  two  ways.  The  body  controls  its  loss  of  heat  as  well  as 
its  production  of  heat  and  under  normal  conditions  both 
means  are  used.  Heat  is  lost  from  the  body  in  the  following 
ways : 

1.  Through  the  excreta  and  waste  of  the  body. 

2.  Through  the  expired  air.     This  air  is  warmer  than  the 
inspired  air. 

357 


358  Healthful  Living 

3.  By  the  evaporation  of  moisture  from  the  skin.     This 
heat  loss  is  increased  with  the  increase  of  perspiration. 

4.  By  conduction  and  radiation  of  heat  from  the  skin. 
We  can  to  some  extent  control  this  heat  loss  through 

evaporation  and  radiation  by  wearing  appropriate  clothing. 
In  winter  the  clothing  should  be  chosen  to  diminish  this 
heat  loss  and  the  material  usually  selected  is  wool.  There 
is  also  automatic  control  of  the  heat  loss  by  reflex  control 
of  the  sweat  nerves  and  the  nerves  to  the  blood  vessels 
(vasomotor  nerves).  These  vasomotor  nerves  are  appar- 
ently under  the  guidance  of  a  special  center,  so  that  a 
greater  or  less  amount  of  blood,  as  desired,  may  be  sent  to 
the  skin.  On  warm  days  the  skin  vessels  are  dilated;  on 
cold  days  they  are  contracted. 

Heat  is  produced  in  the  body  by  oxidation  of  food  materials. 
The  body  burns  its  food  and  so  forms  heat,  and  an  increase 
in  good  food  gives  more  material  for  heat.  Why  do  we  eat 
more  in  cold  weather?  This  heat  production  is  regulated 
by  the  heat  center  or  other  controlling  centers  acting  through 
the  nerves  going  to  the  muscles.  It  is  also  regulated  by  the 
quantity  and  character  of  the  food  eaten  and  this  is  de- 
termined by  the  appetite.  Body  heat,  therefore,  in  its  pro- 
duction and  in  its  loss  is  cared  for  by  the  body.  By  an 
understanding  of  the  physiology  of  the  process,  we  may  so 
act  as  to  assist  the  body.  If  we  act  contrary  to  the  body 
laws,  we  are  working  against  the  body.  Write  down  in  two 
columns  the  ways  in  which  the  body  may  be  assisted  in  heat 
production  and  in  heat  loss. 

The  regulation  of  body  activity  and  growth.  —  It  has  been 
learned  that  there  are  secretions  which  empty  into  the  ali- 
mentary canal  through  ducts  leading  from  the  secretory 
glands.  Now  there  are  other  glands  which  produce  secre- 
tions which  they  give  directly  to  the  blood  stream  and  such 
are  called  internal  secretions.  They  are  discussed  under  the 
chapter  on  special  regulative  processes  because  they  in- 


Some  Special  Regulative  Processes  359 

fluence  the  activity  of  organs  through  the  body;  in  ad- 
dition, some  are  concerned  in  the  phenomena  of  growth  and 
development.  If  you  have  ever  seen  a  cretin,*  you  have 
seen  a  person  who  lacks  one  of  these  internal  secretions, 
that  from  the  thyroid  gland,  situated  in  the  neck.  These 
secretions  are  called  hormones  (from  oTrvaco,  arouse  or  excite) . 

Thyroid  secretion.  —  The  thyroid  is  a  gland  lying  in  the 
middle  line  of  the  neck  and  just  below  the  thyroid  cartilage. 
This  secretion  is  necessary  for  proper  physical  and  mental 
growth. 

Thymus  secretion.  —  The  thymus  is  a  gland  that  develops 
until  the  age  of  12-13  and  then  decreases  in  size.  It  lies 
just  above  the  heart.  This  gland  gives  an  internal  secretion 
that  is  of  great  importance  in  the  development  of  the  child. 

Adrenal  secretion.  —  The  adrenals  are  small  glands  lying 
on  top  of  the  kidneys.  These  glands  give  in  their  secretion 
a  substance,  epinephrin,  which  acts  as  a  stimulant  to  the 
heart  and  blood  vessels  and  serves  to  increase  the  blood 
pressure.  This  gland  becomes  very  active  under  emotional 
conditions.  The  power  that  one  has  when  stimulated  by 
fear  or  excitement  to  do  a  tremendous  physical  feat  is  given 
by  the  epinephrin  from  the  adrenals. 

Pituitary  secretion.  —  At  the  base  of  the  brain,  lies  a 
little  gland,  the  pituitary  gland.  This  gland  has  two  lobes, 
an  interior  (front)  and  a  posterior  (back).  The  posterior 
lobe  furnishes  a  secretion  which  causes  a  rise  in  blood  pres- 
sure and  slowing  of  the  heart  beat.  The  anterior  lobe  ap- 
parently gives  a  secretion  of  importance  in  the  growth  of 
the  body  and  especially  in  the  growth  of  bones.  Increased 
activity  of  this  lobe  of  the  gland  is  responsible  for  giantism.* 

Pancreatic  secretion.  —  The  pancreas  gives  a  duct  secre- 
tion. What  are  its  enzymes?  It  also  gives  a  hormone 
directly  into  the  blood  and  this  hormone  is  concerned  in 
the  oxidation  of  sugar  in  the  body.  Disturbance  of  this 
secretion,  produces  the  disease  known  as  diabetes. 


360  Healthful  Living 

It  will  be  noticed,  therefore,  that  the  human  body  is  very 
complex  in  its  regulation  and  control.  Unseen  forces  are 
at  work  directing  its  growth  and  controlling  its  development. 
It  is  a  mistake  to  believe  that  body  health  and  vigor  may  be 
obtained  by  the  performance  of  formal  gymnastic  exercise 
in  the  home  or  gymnasium.  This  human  body  must  be 
used  with  reference  to  its  controlling  mechanisms  and  its 
evolutionary  development.  If  man  will  use  his  body  in 
natural  and  wholesome  ways  of  exercising  it,  eschewing 
alcohol  and  tobacco,  selecting  good  foods  and  pure  water, 
and  obtaining  fresh  air  and  clean  surroundings,  then  weak- 
ness and  disease  will  not  be  so  common.  The  body  in  this 
way  will  serve,  as  it  should,  as  a  fine  and  splendid  temple 
for  the  soul  and  the  soul  will  be  enriched. 

The  control  of  the  voice.  —  Man  conveyed  ideas  in  primi- 
tive *  times  before  the  use  of  the  voice,  by  gestures.  To-day 
this  is  called  pantomime  and  as  a  means  of  conveying  ideas 
it  is  less  necessary  because  man  has  the  ability  to  express  his 
wants  and  desires  by  the  spoken  word.  The  voice,  there- 
fore, is  the  means  of  communication  between  individuals; 
it  is  not  the  only  means,  however,  nor  should  it  be  used  alone 
because  the  use  of  the  muscles  of  the  body  in  producing 
movement  and  different  forms  of  expression  makes  clearer 
and  more  forceful  the  meaning  of  the  thought  conveyed  by 
the  voice.  The  voice  is  used  to  convey  ideas  in  song,  and 
this  use  is  not  only  utilitarian  but  also  may  be  such  as  to 
give  pleasure.  Now  whether  the  word  is  spoken  or  sung 
there  are  certain  important  facts  in  the  production  of  this 
sound  that  are  to  be  considered.  The  first  of  these  is  the 
breath  by  which  the  sound  is  produced,  the  second  is  the 
larynx  in  which  the  sound  is  produced,  and  the  third  is  the 
resonating  chambers  which  modify  and  mold  the  sound. 
The  voice  may  be  likened  to  a  musical  instrument  in  which 
the  breath  is  the  motive  factor,  the  larynx  is  the  string  in 
the  case  of  a  violin,  and  the  resonators  are  curves  and  flut- 


Some  Special  Regulative  Processes  361 

ings  of  the  horn.  In  certain  respects  the  voice  resembles 
more  a  violin  and  in  others  it  may  be  likened  to  a  horn. 

It  is  verj^  important  that  the  child  learn  to  use  the  voice 
properly  and  to  this  end  there  should  be  instruction  in  speak- 
ing and  singing. 

The  motor  factor  —  breath.  —  For  the  production  of  sound, 
air  must  be  taken  into  the  lungs  and  while  under  control 
it  is  allowed  to  pass  out  over  the  strings  in  the  larynx,  thus 
producing  sound.  In  the  chapter  on  respiration  it  was 
learned  that  there  were  three  ways  of  breathing:  costal, 
abdominal,  and  natural.  Now,  inasmuch  as  the  diaphragm 
is  so  important  in  supporting  the  sound  produced  you  have 
another  reason  why  breathing  should  combine  abdominal 
and  costal.  This  form  of  breathing  will  give  more  air  and 
at  the  same  time  will  have  it  under  better  control.  It  is 
very  important  that  the  parts  of  the  body  be  adjusted  in 
the  proper  way  and  in  this  connection  is  it  important  to 
remember  the  correct  standing  position.  How  often  have 
you  seen  girls  and  boys  who  were  unable  to  speak  plainly? 
Did  you  notice  that  their  standing  position  was  very  poor? 
One  who  wishes  to  have  a  good  voice  must  learn  to  stand 
in  a  position  that  will  allow  the  chest  to  have  free  and  un- 
obstructed movement  and  that  will  keep  the  abdomen  well 
drawn  in.  As  a  result,  the  larynx  will  be  supported  in  the 
proper  place  in  the  throat. 

The  weal  instrument  —  the  larynx.  —  The  larynx,  in 
which  the  voice  originates,  is  a  cartilaginous  box  with  three 
sides,  the  sharpest  corner  forming  a  ridge  in  front  (Fig.  206). 
In  many  persons  the  larynx  is  prominent  in  the  neck,  and 
is  called  the  Adam's  apple.  The  lid  of  the  voice-box,  or 
larynx,  is  also  of  cartilage,  and  is  called  the  epiglottis. 
Across  the  middle  of  the  box  are  stretched  two  bands,  or 
half  curtains,  called  the  vocal  cords  (Fig.  207).  Their  ends 
are  attached  to  the  front  and  back  of  the  larynx.  They-  are 
not  true  cords,  however,  as  they  are  thin  and  flat,  and  one 


362 


Healthful  Living 


Epiglottis 
ffyoicf  JBor» 


edge  of  each  band  is  attached  to  the  side  of  the  larynx. 

Since  the  cords  run  across  the  middle  of  the  chamber  from 

front  to  back,  the  free  edges 
are  brought  near  together. 
The  slit,  or  opening  between 
these  edges,  is  called  the 
glottis.  During  ordinary 
respiration  the  cords  are  re- 
laxed and  the  slit  is  wide 
open.  To  make  the  voice, 
the  vocal  cords  must  be 
brought  very  near  together 
and  drawn  tight,  and  a  cur- 
rent of  air  must  be  forced 
through  the  narrow  slit  to 
throw  the  cords  into  vibra- 
tion. The  front  ends  of  the 


Larynx 


Cricoid  Cortifaae 


FIG.  206.  —  View  of  the  right  side 
of  the  larynx,  from  the  front. 


cords  are  attached  to  the 
larynx  just  within  the  angle, 
or  ridge,  called  the  Adam's  apple.  The  rear  ends  are 
attached  to  two  little  movable  cartilages  at  the  back  of 


Left 
Vocg/Cord 


Right 
Voca/  Cord 


Arytenoid 
Carti/age 


207.  —  Cross-section  of  the  larynx  above  the  vocal  cords, 
with  the  mucous  membrane  removed. 


Some  Special  Regulative  Processes  363 

the  chamber.  The  moving  of  these  little  cartilages  by  the 
muscles  of  the  larynx  brings  the  edges  together  and  tightens 
the  cords. 

Sound  waves,  or  sound  vibrations,  are  imparted  to  the 
air  by  the  tremulous  motion  of  the  cords.  The  limits  of 
the  vibrations  which  the  human  voice  is  capable  of  making 
are  from  42  vibrations  per  second  for  the  lowest  tone,  to 
over  2000  vibrations  per  second  for  the  highest  tone.  Lower 
C  of  the  soprano  is  produced  by  256  vibrations  per  second. 
The  limits  of  vibrations  which  the  human  ear  is  capable  of 
hearing  are  from  16  to  50,000  vibrations  per  second,  but 
until  they  reach  a  rate  of  about  50,  the  sound  is  more  like  a 
buzz  than  a  tone.  Some  people  cannot  hear  the  voice  of 
mice,  or  the  squeak  of  a  bat,  because  the  high  pitch  is  be- 
yond the  limit  of  their  hearing. 

The  resonant  chambers.  —  The  vibration  of  the  vocal 
cords  alone  produces  a  weak,  squeaky  sound,  but  their  vi- 


FIG.  208.  —  The  shape  of  the  mouth  in  sounding  the  vowels  a,  e,  oo. 

brations  are  reenforced  or  strengthened  by  the  vibration 
of  the  walls  of  the.  lungs  and  trachea  below,  and  of  the  nose 
and  mouth  above  (Fig.  208).  These  echoes,  combining 
with  and  ree'nforcing  the  vibration  of  the  cords,  determine 
the  quality  of  the  voice.  Just  as  the  shape  and  material 
of  the  walls  of  the  violin  give  the  quality  to  its  tone,  so  the 
shape  and  condition  of  the  nasal  passages,  throat,  etc.,  give 


364 


Healthful  Living 


characteristic  quality  to  each  human  voice  (Fig.  209).  If 
the  nasal  passages  are  stopped  up  by  catarrh,  the  person 
is  said  to  speak  in  a  nasal  tone,  or  through  the  nose,  but 
a  "  nasal  "  tone  really  results  only  when  the  sound  can- 
not come  through  the  nose.  Such  a  person's  voice  does  not 
change  its  quality  when  he  speaks  with  his  nose  stopped 
with  his  fingers.  But  a  voice  which  has  correct  nasal 
resonance  *  will  change  its  quality  when  the  nostrils  are  held. 
Try  it,  and  see  whether  your  voice  retains  its  nasal  resonance. 
Let  one  pupil  read  aloud  at  the  back  of  the  room  where  the 


FIG.  209.  —  The  resonant  chambers.  A,  resonance  cavity  of  the  nose; 
B,  resonance  cavity  of  the  mouth ;  C,  resonance  cavity  of  the  pharynx ;  D, 
soft  palate  ;  E,  tongue  ;  F,  point  at  which  vibration  begins. 

The  figure  on  the  left  shows  soft  palate  (D)  in  normal  position,  allowing 
air  in  iiaso-pharynx  to  vibrate  in  unison  with  initial  note.  The  middle 
figure  shows  soft  palate  raised,  shutting  off  the  resonance  and  rendering  tone 
thin  and  hard.  The  figure  on  the  right  shows  another  common  fault.  The 
tongue  is  lowered,  increasing  the  size  of  the  mouth  cavity.  This  increases 
the  volume  of  the  tone,  but  renders  the  quality  harsh  and  hollow  (Latson). 

others  do  not  see  him,  and  find  whether  they  can  tell,  by  the 
change  in  his  voice,  at  which  word  he  closes  his  nostrils  in  the 
midst  of  the  reading.  The  vocal  cords  are  not  used  at  all 
in  whispering.  It  is  akin  to  whistling.  In  singing,  single 
sounds  are  more  or  less  prolonged.  In  speech,  the  principal 
changes  are  in  the  duration  of  the  sound,  and  in  the  reso- 
nance in  the  mouth.  In  whispering,  audible  breathing  is  cut 


Some  Special  Regulative  Processes  365 

off  by  the  tongue  and  lips,  and  words  are  articulated,  al- 
though no  sound  comes  from  the  vocal  cords.  A  public 
speaker  ordinarily  utters  125  words  per  minute.  If  there 
are  four  sounds  to  a  word,  this  amounts  to  500  sounds  each 
minute  or  eight  each  second. 

Pitch,  volume,  and  quality.  —  The  rate  of  vibration  of  a 
cord,  and  hence  the  pitch  of  a  sound,  are  influenced  in  several 
ways.  Is  the  string  of  a  violin  or  of  a  guitar  tuned  up  or 
down  by  tightening  it?  Which  is  higher  in  pitch,  a  long 
or  short  string  of  a  harp  or  a  piano  ?  Which  makes  a  higher 
note,  the  light  or  the  heavy  string  of  a  violin  or  a  guitar? 
The  pitch  of  the  note  given  by  a  string  may  be  raised  in 
three  ways  :  tightening,  shortening,  or  decreasing  the  weight 
of  the  string.  From  these  facts  explain  why  the  voice  rises 
in  pitch  when  we  are  excited,  the  muscles  at  that  time  be- 
ing contracted  with  greater  force.  Why  does  a  cold  with 
congestion  of  the  cords  cause  a  person  to  speak  in  a  hoarse, 
deep  voice?  Why  does  a  man,  whose  larynx  is  larger  than 
a  woman's,  have  the  deeper  voice?  Why  does  a  boy's  voice 
change  as  his  larynx  enlarges? 

A  man's  voice  has  usually  a  pitch  of  one  octave*  below 
that  of  a  woman  or  a  boy.  The  range  of  the  human  voice 
is  about  two  octaves.  The  voice  may  also  vary  in  volume, 
or  loudness,  as  well  as  in  pitch.  How  do  we  speak  loudly 
at  one  time  and  softly  at  another?  If  a  tin  pan  is  struck 
gently,  the  sound  is  weak;  if  it  is  struck  with  force,  the 
sound  is  louder.  We  make  the  voice  louder  by  stronger 
expiration  of  the  breath,  thus  sending  the  air  with  more 
strength  against  the  tightened  vocal  cords.  Two  persons 
sing  a  song  together  in  the  same  pitch  and  with  the  same 
loudness ;  yet  you  can  readily  distinguish  a  difference  in 
the  two  voices.  This  is  because  of  a  difference  in  quality, 
which  is  the  third  variation  possible  in  a  voice.  Sound  in 
wind  instruments  is  strengthened  by  resonance,  which  is  a 
kind  of  instantaneous  echo  in  the  pipes. 


366  Healthful  Living 

The  care  and  culture  of  the  voice.  —  The  voice  should  not 
be  used  more  than  is  absolutely  necessary  when  it  is  hoarse. 
Catarrh  may  injure  the  voice  by  injury  to  the  vocal  cords 
or  by  obstruction  of  the  nasal  passages. 

The  best  way  for  a  child  to  acquire  distinct  and  refined 
speech,  is  to  hear  it  habitually.  Great  numbers  of  people 
are  handicapped  by  hasty,  harsh,  indistinct,  or  disagreeable 
speech.  Parents  and  teachers  should  remember  as  children 
are  growing  up,  what  an  advantage  to  them  in  after  life  a 
refined,  melodious  voice  will  be.  Nearly  all  children  have 
sweet  voices  when  young,  but  many  lose  them  before  adult 
life  on  account  of  acquired  nervous  habits,  dusty  and  ill- 
ventilated  rooms,  deformity  of  lungs  due  to  restrictive 
clothing,  or  from  singing  during  the  time  their  voices  are 
changing  or  attempting  tunes  beyond  the  compass  of  their 
voices. 

Smokers  are  frequent  sufferers  from  affections  of  the 
throat.  Smoking  may  produce  a  constant  "  hacking " 
cough.  The  hot,  poisonous  smoke,  to  say  nothing  of  the 
poisonous  vapor  of  nicotine,  brought  in  contact  with  the 
vocal  cords,  is  almost  certain  to  produce  mischief.  Singers 
and  public  speakers  usually  have  to  give  up  the  use  of  tobacco 
on  this  account.  Cigarette  smoking  is  especially  bad  for 
the  voice,  as  the  smoke  is  inhaled. .  The  deep-toned  voice 
of  the  chronic  drinker  may  be  an  indication  of  inflammation 
of  the  larynx,  a  disease  from  which  beer  drinkers  often  suffer. 

Methods  of  voice  training  vary,  but  it  should  be  noted 
that  there  is  no  special  virtue  in  any  one  system.  To  train 
the  voice  properly  there  must  be  considered  the  motor 
factor,  the  vocal  instrument,  and  the  resonant  chambers. 
In  some  pupils  one  factor  may  need  more  emphasis  than 
the  others  and  the  successful  teacher  will  meet  the  needs 
of  the  pupil  rather  than  pursue  with  every  pupil  a  rigid 
system.  To  secure  a  rich,  resonant,  and  flexible  voice  is 
the  goal.  Hence  there  must  be  no  straining  and  no  tense- 


Some  Special  Regulative  Processes  367 

ness.     Breathing  exercises  that  call  for  a  rigid  over-filled 

chest  destroy  flexibility.  Swedish  formal  gymnastics  are 

distinctly  harmful  in  this  respect  because  they  make  the 
individual  tense  and  rigid. 


GLOSSARY 

Cretin.  —  A  person  suffering  from  cretinism.  This  condition  is 
caused  by  a  deficiency  in  the  secretion  of  the  thyroid  while 
the  individual  is  a  child. 

Giantism.  —  A  condition  of  the  body  in  which  all  parts  are  enlarged 
and  the  person  appears  as  a  giant.  This  condition  results 
from  disturbed  secretion  of  the  pituitary  gland. 

Octave.  —  The  interval  between  any  note  and  that  note  that  gives 
twice  as  many  or  hah3  as  many  vibrations  in  a  second. 

Primitive.  —  Pertaining  to  the  earliest  times,  especially  before 
modern  or  ancient  civilization. 

Resonance.  —  A  prolongation  or  reinforcement  of  sound  by  means 
of  sympathetic  vibration.  The  vibrations  of  the  resonating 
chamber  must  come  at  the  same  time  as  the  vibrations  of  the 
instrument  producing  the  sound. 


CHAPTER  XIX 
BACTERIA   AND    DISEASE 

I.    Injury  to  the  Body  by  Forces  in  Its  Environment, 
II.   Microscopic  Forms  of  Life. 
Molds 
Yeasts 
Bacteria 
The  work  of  these  organisms 

III.  The  Effects  of  Bacterial  Growth  in  the  Body. 

Ptomaines 
Toxins 

IV.  The  Germ  Theory  of  Disease. 
V.   Antitoxins  and  Immunity. 

Smallpox  vaccination 

Typhoid  vaccination 
VI.    Injury  of  the  Body  by  Poisons  in  Food. 

Fish  and  shellfish 

Meat  poisons 

Poisons  in  milk 
VII.    Injury  of  the  Body  by  Physical  Agents. 

Heat  exhaustion 

Sunstroke 

Electricity  , 

Mountain  sickness 

Caisson  disease 
VIII.    Injury  of  the  Body  by  Chemical  Agents. 

Lead  poisoning 

Other  poisonous  metals 
IX.   Diseases  Caused  by  Mosquitoes. 

Malaria 

Yellow  fever 
X.   Tuberculosis. 
XL   Prevention  of  Communicable  Diseases. 

Cleanliness  of  the  mouth 
368 


Bacteria  and  Disease  369 

Drinking  water 
Food 

Care  of  the  bowels 
Bathing 
Sleeping 

Prevention  of  influenza 

XII.    Table  of  Ways  and  Means  of  Communication  of  the  Im- 
portant Infections  of  Man. 

XIII.  How  Bacteria  Are  Destroyed  Within  the  Body. 

XIV.  How  Bacteria  Are  Destroyed  Outside  the  Body. 

Disinfection 
Antiseptics 

XV.    A  Curious  Theory  of  Disease. 
XVI.    Health  Rules  for  School  Children. 


Injury  to  the  body  by  forces  in  its  environment.  —  It  is 
very  important  to  remember  that  the  human  body  is  the 
kind  of  bod}r  it  is,  because  of  the  way  in  which  the  members 
of  the  race  have  lived.  For  example,  man  has  an  alimentary 
canal  that  requires  a  mixed  diet,  partly  because  in  the  growth 
and  development  of  the  alimentary  tract,  a  diet  of  flesh, 
vegetables,  grains,  nuts,  and  fruits  is  used.  Now  the  body 
is  injured  if  man  in  his  foolishness  tries  to  live  only  on  nuts. 
Also  the  body  of  man  has  developed  with  reference  to  exercise. 
Man  has  inherited  the  need  for  exercise  just  as  definitely 
as  he  has  inherited  his  biped  position.  Therefore,  the  man 
or  woman  who  sits  in  an  office  all  day  and  does  not  par- 
ticipate in  games  or  sports  or  gymnastics  of  any  kind,  will 
suffer  from  disturbances  in  the  body  due  to  the  lack  of 
physical  exercise. 

The  body  may  also  be  injured  by  attacks  from  forces  out- 
side the  body,  such  as  bacteria.  These  minute  microscopic 
animals  are  present  in  the  air  and  water  and  are  often  found 
on  objects  of  all  kinds.  They  cause  disease  by  obtaining 
an  entrance  into  the  body  and  growing  there.  As  they 
grow  they  produce  poisons,  which  passing  into  the  blood 
2s 


370 


Healthful  Living 


in  the  circulation,  injure  the  body  cells  and  in  some  cases 
kill  them.  Protection  from  such  forces,  therefore,  will  be 
obtained  by  preventing  these  bacteria  from  obtaining  en- 
trance to  the  body  or  by  keeping  the  body  so  well  that, 
if  they  do  get  in,  they  cannot  grow  and  develop.  Do  you 
remember  the  parable  of  the  sower  ?  Well,  bacteria  are  like 
seed.  If  they  fall  on  stony  ground  (good,  vigorous,  healthy 
bodies)  they  die;  if  the  leucocytes  and  protective  agents 
in  the  blood  are  able  and  sufficient,  they  will  play  the  part 
of  tares  and  birds  in  destroying  the  bacteria;  but  if  the 
bacteria  come  into  the  lazy,  weak,  inefficient  body,  they 
will  produce  many  fold. 

Microscopic  forms  of  life.  —  As  we  trace  back  to  their 
origins  the  lines  of  development  of  the  animal  and  plant 
kingdoms,  we  find  them  converging  to  one  common  type, 
a  single  cell  organism,  so  simple  in  construction  and  so  un- 
specialized  in  function  that  it  is  impossible  to  tell  whether 
it  is  plant  or  animal.  These  cells  are  so  small  that 
they  can  only  be  observed  by  means  of  the  high  power  of 
the  microscope.  They  are  much  smaller  than  the  cells  of 
the  body.  There  are  many  different 
forms,  but  the  ones  important  for  us  to 
know,  are  molds,*  yeast,  and  bacteria. 

Molds.  —  Every  one  has  seen  fungus  * 
plants,  such  as  mushrooms  and  puffballs, 
that  do  not  bear  flowers  but  multiply  by 
spores.  They  live  upon  dead  logs  or  where 
there  is  much  dead  organic  matter  in  the 
soil.  Imagine  a  fungus  that  grows  on  an 
average  about  ^  of  an  inch  in  height ;  this 
is  called  mold  (Fig.  210).  It  grows,  for  in- 
stance, upon  moist  bread  in  warm  weather. 
Mold  forms  a  kind  of  network  as  it  grows 
through  any  substance  that  will  nourish  it,  and  sends  up  stalks 
with  knoblike  ends,  the  knobs  being  full  of  minute  spores. 


FIG.  210.  — Ring- 
worm fungus  in  a 
hair. 


Bacteria  and  Disease 


371 


Yeast.  —  Think,  if  you  can,  of  small  plants  only  about 
of  an  inch  in  length,  and  composed  usually  of  one  oval 
cell,  a  plant  that  makes  new  plants  by  "  budding,"  or  the 
forming  of  a  smaller  cell  on  the  old  one. 
Yeast  cakes  consist  of  yeast  plants  scattered 
among  the  grains  of  flour  of  which  the  cake 
was  made.  Yeast  plants  multiply  rapidly, 
doubling  in  number  in  Iwo  hours  (Fig.  211). 
They  grow  upon  sugar,  decomposing  it  into 
alcohol  and  carbon  dioxide.  This  process 

called   fermentation.     In   wine   making, 


s 


FIG.  211.  — The 
yeast  plant. 


alcohol  is  the   product  sought;    in    bread 

making,  carbon  dioxide  is  the  useful  product, 

this  gas  giving  the  bread  its  lightness,  while  the  small  amount 

of  alcohol  formed  is  driven  out  by  the  heat  in  cooking. 
Bacteria.  —  But  suppose  the  microscope  shows  a  much 

smaller  organism 
which  averages 

aoAoo  of  an  inch  in 
diameter,  a  one-celled 

organism  that  multi- 
plies by  division  like 
the  amoeba  and  other 
one-celled  animals, 
and  lives  upon  albu- 
minous substances; 
only  for  its  food, 
This  is  a  bacterium. 
Bacteria  are  called 
also  microbes  *  or 
germs  ;  and  they  are 


FIG.  212.  -The  organism  that  causes  pneu- 
monia  is  a  micrococcus  and  is  called  the  pneu- 
mococcus.  These  bacteria  have  a  capsule 
surrounding  the  organism.  The  large  cells  are 
polymorphonuclear  leucocytes. 


the 
ing 


smallest    of    liv- 
organisms.         A 

that      k 
.tU1U      L 

rod-shaped    is    Called 


372 


Healthful  Living 


a  bacillus  ;  a  round-shaped  bacterium  is  called  a  micrococcus ; 
and  if  spiral,  it  is  called  a  spirillium  (Figs.  212,  213,  214). 
Under  favorable  conditions  —  abundance  of  food  and  con- 
siderable warmth  and  moisture  —  bacteria  may  double  in 
numbers  every  half  hour.  Thus  millions  may  result  from 
even  one  in  a  short  time.  (You  will  comprehend  this  better 
by  referring  to  "geometrical  progression"  in  your  arith- 
metic.) Dryness  and  cleanliness  prevent  their  growth ;  cold 

retards  their  growth 
and  division,  hence 
the  utility  of  ice  in 
preserving  meat, 
milk,  fruits,  and 
other  foods  in  warm 
weather. 

Can  you  now  ar- 
range the  names 
yeast,  mold,  and  bac- 
terium in  order  of 
size?  Can  you  give 
the  kind  of  material 
that  each  uses  for 
,  food?  Can  vou  tell 

FIG.  213.  —  These    bacteria  are  the  cause  of  " 

cholera  and   are  called  cholera  spirilla.      They  DOW  each  multiplies, 

have  small  hair-like  processes  which  serve  as  tails  Qr       reproduces       its 
for  locomotion.     These  are  called  flagellae. 

kind?      What    is    a 
bacillus?     For  what  is  "  microbe  "  another  name? 

The  work  of  these  organisms.  —  Molds  are  nature's  tools 
for  destroying  hard  and  durable  tissue  like  logs,  bone,  and 
hides,  which  otherwise  would  not  decay  but  would  fill  the 
earth,  leaving  no  room  for  living  creatures.  Ringworm  is 
caused  by  the  growth  of  one  form  of  mold  within  the  skin. 
It  does  not  grow  in  a  sound  and  clean  skin.  Falling  of  the 
hair  is  often  accompanied  by  the  growth  of  mold  in  the  hair 
follicles,  but  it  must  be  preceded  by  overheating  and  starving 


Bacteria  and  Disease 


373 


of  the  cells  of  the  scalp  by  a  tight  hat,  too  much  brain  work, 
or  other  cause.  Yeast  prevents  the  calamity  of  all  plant 
food  accumulating  in  the  form  of  starch  and  sugar.  Bacteria 
destroy  the  dead  and  excreted  matter  of  vegetables  and 
animals  so  that  it  melts  away  and  is  stored  in  the  soil,  ready 
to  be  utilized  as  plant  food  again.  Mold,  yeast,  and  bac- 
teria are  great  blessings,  for  they  are  indispensable  friends 
of  all  other  living 
beings.  They  do 
not  always  wait  for 
the  dead  or  dying 
material  to  be  ex- 
creted, or  separated 
from  the  animal  or 
plant,  before  attack- 
ing and  destroying 
it.  If  more  food  is 
eaten  than  can  be 
digested,  and  it  re- 
mains longer  than 
five  hours  in  the 


FIG.  214.  —  The  diphtheria  bacilli  are  the 
small  rods  shown  in  the  picture.  These  organ- 
isms are  killed  by  antitoxin  given  to  those  who 
have  the  disease. 


stomach,        starchy 

food     may    ferment 

by     the    action    of 

yeast   plants,  giving 

rise  to  carbon  dioxide  gas,  and  albuminous  .food  may  undergo 

decomposition  from  the  action  of  bacteria. 

The  effects  of  bacterial  growth  in  the  body. — Ptomaines* — 
You  learned  that  bacteria  produce  decay  in  unsound  tissue. 
They  destroy  the  albumin  in  which  they  grow,  producing 
foul-smelling  gases  and  a  number  of  poisons  called  ptomaines, 
if  formed  after  death.  Ptomaines  cause  most  of  the  symp- 
toms produced  by  eating  decayed  meat.  A  special  kind  of 
ptomaine  sometimes  forms  in  milk  and  ice  cream  which 
been  kept  for  a  long  while.  This  is  why  ice  cream 


374 


Healthful  Living 


which    has    been    melted,   and    frozen   a   second   time,   is 

dangerous. 

Toxins*  —  The  growth  of  bacteria  in  an  unsound,  living 

body,    produces   poisons    called   toxins,    which,    circulating 

among  the  sound  tissues,   produce  weakness  and  disease. 

Disease  germs  may  grow  upon  the  injured  cells  in  an  open 

wound,  causing  offen- 
sive matter  to  form. 
Diphtheria  (Fig. 
214),  typhoid  fever 
(Fig.  215),  tuber- 
culosis (Fig.  225), 
cholera*  (Fig.  213), 
lockjaw*  (Fig.  216), 
and  la  grippe*  are 
all  diseases  in  which 
germs  have  been 
proved  to  be  present, 
and  all  produce  poi- 
sonous toxins. 

The    germ    theory 
FIG.    215.  —  Typhoid    bacilli.     The    growth     Qf     disease. Loilis 

of   these  organisms  in   the  intestine  produces 

typhoid  fever.  Pasteur,    the     great 

French  scientist, 

made  possible  the  modern  understanding  of  disease  and 
opened  up  the  way  for  the  treatment  of  many  diseases  that 
had  caused  scourges  and  plagues  *  in  the  past.  Robert  Koch 
explained  and  demonstrated  the  "  germ  theory  of  infectious 
diseases  "  mainly  as  follows  : 

1.  Each  infectious  disease  is  caused  by  a  specific  germ. 
These  germs  may  be  found  in  the  tissues  or  fluids  of 
the  body  affected  and  the  products  from  the  growth 
of  these  germs  are  the  poisonous  agents  which  injure 
the  body  and  give  the  symptoms  of  the  disease. 
The  germ  of  diphtheria  is  the  Diphtheria  Bacillus.  The 


Bacteria  and  Disease 


375 


poisons  from  the  growth  of  these  germs  in  the  throat  give  the 
symptoms  of  the  disease. 

2.  The  specific  germ  taken  from  one  body  and  introduced 
into  another  body  susceptible  to  the  disease,  will 
produce  in  the  second  body  the  same  disease. 

Why  do  we  have  quarantine  ?  *  In  a  recent  epidemic  of 
infantile  paralysis  in  New  York  City,  a  mother  fearing  to 
take  her  child  to  a 
hospital  left  her 
home  and  traveled 
with  the  sick  child 
to  another  part  of 
the  city.  Why 
should  she  not  have  /  ~  /,._o, 

done  this  ?     Did  she  /  I    / ,          f  /<f  /      i  / 

expose  other  children 
to  the  disease? 
Should  she  have 
been  as  thoughtful 
of  other  children  as 
of  her  own  child? 

Why  should  we 
not  swap  apples  or 
borrow  handker- 
chiefs ? 

Antitoxins  *  and  immunity.*  —  Now  it  is  known  that  one 
attack  of  smallpox  makes  it  impossible  or  very  difficult  for 
that  individual  to  have  the  disease  again.  This  is  true  in 
the  main  for  all  the  communicable  diseases.  This  protec- 
tion against  disease  is  called  immunity,  and  is  due  to  the 
fact  that  the  body  manufactures  protective  substances  to 
kill  the  toxins  (poisons)  produced  by  the  germs  (bacteria). 
These  protective  substances  are  called  antitoxins  and  the 
individual  is  said  to  b3  immune.  This  is  an  active  immunity, 
developed  by  the  individual  himself  in  the  course  of  the 


FIG.  216.  —  Tetanus  is  commonly  called 
"lockjaw."  It  is  caused  by  the  bacilli  shown 
here.  The  "drum  stick"  form  is  characteristic 
of  the  tetanus  bacillus. 


376  Healthful  Living 

disease.  Now  it  is  possible  to  grow  these  substances  in  an- 
other animal  and  then  use  the  serum  *  from  the  blood  of  the 
animal  and  inject  it  into  man.  This  will  give  him  a  passive 
immunity  to  the  threatened  disease.  This  procedure  is  used 
in  diphtheria  epidemics.  Smallpox  vaccination  *  consists  in 
putting  the  smallpox  virus  in  a  small  abrasion  of  the  arm. 
This  produces  the  disease  in  a  mild  form  and  for  about  seven 
years  protects  the  body  by  the  immunity  conferred. 

Smallpox  vaccination.  —  In  1776,  E.  Jenner  of  Berkeley, 
England,  learned  that  the  milkmaids  of  the  shire  considered 
accidental  cowpox,  caught  while  milking,  a  sure  preventive 
of  smallpox.  Twenty  years  later  he  began  to  vaccinate  with 
cowpox  material  to  prevent  smallpox.  Vaccination  protects 
only  for  a  few  years.  If  exposed  to  smallpox,  one  should  be 
vaccinated,  unless  he  has  been  vaccinated  within  the  last 
few  years.  Arm  to  arm  vaccination  is  dangerous.  Only 
fresh  virus  from  healthy  cows  should  be  used.  If  the  arm 
becomes  very  much  swollen  and  disabled,  it  is  a  sign  that 
the  blood  has  been  poisoned  by  the  use  of  impure  material. 
Some  people  are  inclined  to  refuse  vaccination  for  smallpox 
(Fig.  217).  Their  argument  is  that  there  is  no  danger  now 
and  they  do  not  wish  to  inconvenience  themselves  or  run 
even  the  slightest  risk.  This  is  a  very  selfish  attitude. 
There  is  little  danger  to-day  from  smallpox,  but  this  con- 
dition of  safety  has  been  obtained  by  the  systematic  vac- 
cination of  people.  Only  a  selfish  person  would  wish  to 
derive  security  by  the  work  and  service  of  others  and  would 
refuse  to  contribute  his  share  for  the  safety  of  all. 

Typhoid  vaccination.  —  Typhoid  vaccination  has  produced 
remarkable  results  in  this  respect  also.  Years  ago  in  war, 
more  soldiers  died  from  typhoid  than  from  bullets.  To-day 
in  the  armies  of  France,  England,  and  Germany,  typhoid 
is  practically  unknown  due  to  the  use  of  typhoid  vaccina- 
tion. Such  evidence  is  important.  The  history  of  civiliza- 
tion with  its  plagues,  its  Black  Death  and  typhoid  deaths  in 


Bacteria  and  Disease 


377 


PRUSSIA 

HOLLAND 

AUSTXfA 

With  compulsory  vaccination 
and  re-vaccination  at  12yrs. 

With  compulsory  vaccination 
before  entering  school. 

Without  compulsory 
vaccination. 

Be, 
the 

rore 
Low- 

Bet 

the 

fore 
Law 

After  the  Law 

After  the  Law 

of  1S73 

of  1873 

waspassed. 

wasp&ssed. 

Mi,  .,ni 

l.l.i 

1868- 

in<or-oocr>o  —  <NPT*inio 

1866- 

1868- 

1874 

CO 

1872 

2 

1874 

0 

Average 

AnnualDeaths 

Average 

Annual  Deaths 

Average 

AnnualDeoths 

Yearly 
Deaths 
from 

from 

Yearly 
Deaths 
from 

from 
Sma//pox. 

Yearly 
Deaths 
from 

from 
Sma//pox. 

Smallpox 

Smallpox 

Smallpox 

FIG.  217.  —  Table  showing  value  of  vaccination  (Carsten). 


378 


Healthful  Living 


wars  proves  by  contrast  the  value  of  the  preventive  measures 
in  use  to-day. 

The  value  of  vaccination  against  typhoid  is  shown  in  a 
report  of  Major  Jester  covering  the  period  from  1908  to 
1914. 

VACCINATION  AGAINST  TYPHOID  IN  THE  U.  S.  ARMY 


YEAH 

NUMBER  OF 
PERSONS  VAC- 
CINATED 

NUMBER  RE- 
CEIVING THREE 
DOSES 

CASES  op 
TYPHOID 
FEVER 

ARMY,  MEAN 
STRENGTH 

1908  i 

0 

0 

239 

74,692 

19091 

830 

621 

282 

84,077 

1910  i 

16,093 

11,932 

198 

81,434 

1911  ! 

27,720 

25,779 

70 

82,802 

19122 

40,057 

All 

27 

88,478 

1913  2 

25,086 

All 

4 

90,752 

1914  2 

35,902 

All 

7 

92,877 

Injury  of  the  body  by  poisons  in  food.  —  Food  that  is  not 
fresh  undergoes  fermentation  and  decomposition.  In  this 
change  poisons  are  formed  which  taken  into  the  body  cause 
disturbances  and  in  some  cases  death  results. 

Fish  and  shellfish.  —  Fish  that  is  not  fresh  should  not  be 
eaten.  The  signs  of  freshness  in  a  fish  are  firmness  of  the 
flesh,  protruding  eyes,  red  gills,  and  a  clean  fish.  Mussels, 
oysters,  and  lobsters  decompose  rapidly  and  produce  serious 
illness  unless  absolutely  fresh. 

Meat  poisons.  —  Animals  that  are  ill,  should  never  be  used 
for  food.  Meat  that  is  spoiled  is  unwholesome  and  should 
not  be  eaten.  Sausages  and  other  made  meats  are  less 
wholesome  than  fresh  meats. 

Poisons  in  milk.  —  Milk  may  carry  germs  and  in  this 
way  infect  persons  using  the  milk.  To  prevent  this  the 

1  Voluntary  vaccination.        2  Compulsory  vaccination. 

In  the  years  1908-1911  the  vaccination  was  voluntary.  Beginning  in  1912, 
it  has  been  compulsory.  Since  1912,  the  cases  of  typhoid  27,  4,  7  were  in 
men  who  were  not  vaccinated,  for  some  reason  or  other,  or  who  had  con- 
tracted the  disease  before  enlistment,  with  few  exceptions. 


Bacteria  and  Disease 


379 


milk  is  often  pasteurized  *  (heated  from  150°  to  155°  F.  for 
20-30  minutes).  In  preventing  the  transmission  of  dis- 
ease germs,  greater  emphasis  should  be  placed  on  the  method 
of  obtaining  the  milk.  The  dairyman  should  have  clean 
pails,  and  clean  hands,  and  the  udder  of  the  cow  should  be 
cleaned  before  milking.  The  farmer  who  takes  the  milk 
pail  from  the  fence  and,  without  washing  his  hands,  milks 
the  cow  which  has  been  standing  in  a  dirty  stable,  is  not 
getting  clean  milk.  Furthermore,  he  is  neglecting  a  duty  and 
responsibility  he  owes  to 
his  family  and  his  neigh- 
bors. 

The  poisons  and  dirt 
in  milk  are  real  sources 
of  danger  to  the  body, 
but  they  can  be  elimi- 
nated by  careful  gather- 
ing and  distribution  of 
the  milk  supply.  The 
cows  should  be  cared  for 
in  a  sanitary  stable  and 
every  means  used  to  keep 
them  clean  and  healthy. 
Cows  should  be  cleaned  preparatory  to  milking.  Covered 
pails  for  milking  should  be  used  in  order  to  keep  the  milk 
free  from  dirt  (Fig.  218). 

It  is  also  very  important  to  keep  the  milk  clean  after  it 
is  gathered.  All  bottles  should  be  sterilized  *  and  the  hands 
should  not  come  in  contact  with  the  milk  or  inside  of  the 
bottle.  The  best  method  of  bottling  milk  is  by  machinery. 
Milk  is  sometimes  sold  in  bulk,  from  cans.  Such  milk, 
even  if  gathered  carefully,  is  liable  to  be  contaminated.  Flies 
and  dirt  should  not  gain  access  to  the  milk  at  any  time. 
Compare  the  two  pictures  in  Figure  219  and  be  prepared 
to  state  all  the  advantages  in  the  method  shown  in  the  lower 


FIG.  218.  —  Two  kinds  of  milk  pails. 
%£  ;  the  cov- 


Healthful  Living 


picture.  In  spite  of  the  care  exercised  in  many  places  in 
gathering  the  milk,  a  certain  amount  of  infectious  material 
gains  entrance  to  the  milk  after  it  is  gathered.  To  prevent 


Courtesy  of  Metropolitan  Life  Ins.  Co. 
FIG.  219.  —  Two  ways  of  distributing  milk. 

these  organisms  getting  into  the  body  and  so  causing  dis- 
ease, pasteurization  is  very  widely  practiced.  Communi- 
ties after  pasteurizing  the  milk  supply  have  noticed  a  drop 


Bacteria  and  Disease 


in  the  amount  of  sickness  and  number  of  deaths.  When 
the  infants  in  the  care  of  the  City  of  New  York  (Randall's 
Island)  were  fed  on  milk  that  was  not  pasteurized  the  death 
rate  was  as  follows  : 


YEAR 

NUMBER  OP 
CHILDREN 

NUMBER  op 
DEATHS 

PER- 
CENTAGE 

1895 

1216 

511 

42.02 

1896 

1212 

474 

39.11 

1897 

1181 

524 

44.36 

Total 

3609 

1509 

41.81 

This  milk  was  gathered  from  a  carefully  selected  herd  pas- 
tured on  the  island.  In  the  early  part  of  1898  a  pasteuriz- 
ing plant  was  installed  on  the  island  and  the  milk  given  to 
the  children  was  pasteurized.  No  other  change  was  made 
in  the  diet.  The  record  for  the  next  seven  years  was  as 
follows : 


YEAB 

NUMBER  op 
CHILDREN 

NUMBER  OF 
DEATHS 

PER- 
CENTAGE 

1898 

1284 

255 

19.80 

1899 

1097 

269 

24.54 

1900 

1084 

300 

27.68 

1901 

1028 

186 

18.09 

1902 

820 

181 

22.07 

1903 

542 

101 

18.63 

1904 

345 

57 

16.52 

Total 

6200 

1349 

21.04 

It  will  be  noticed  that  the  total  number  of  deaths  in  seven 
years  is  less  than  the  total  in  three  years  with  raw  milk. 
Professor  Fisher  gives  the  value  of  a  human  life  in  dollars 


382  Healthful  Living 

as  being  $950  at  the  age  of  five  years.  Counting  the  average 
of  these  infants  to  be  five  years,  what  was  the  yearly  sav- 
ing to  the  city  by  the  installation  of  this  plant.  Beyond  this 
hypothetical  saving  there  was  a  real  saving  in  nursing  and 
hospital  supplies,  medical  care,  and  the  cost  of  burial. 

Injury  of  the  body  by  physical  agents.  —  The  body  may 
be  injured  by  forces  coming  in  contact  with  it  from  the  out- 
side. These  forces  may  be  bacteria  or  they  may  be  heat, 
chemical,  etc.  The  prevention  of  injury  due  to  physical 
forces  will  be  important  and  of  value  in  maintaining  our 
health. 

Heat  exhaustion.  —  The  main  cause  in  this  is  heat.  It 
may  come  from  the  sun  or  from  a  furnace.  Individuals  who 
indulge  in  alcohol  are  easily  attacked.  It  occurs  often  in 
armies  on  the  march.  Clothing  fit  only  for  cold  weather 
worn  on  hot  days  predisposes  one  to  sunstroke. 

Sunstroke.  —  This  condition  is  caused  by  the  sun's  rays. 
Care  must  be  taken  not  to  expose  the  body  to  too  great 

465  Cases  of  Sunstroke,  1896 

Heavy  Dr/nkers  3O%  Moderate  Drinkers  50%  Abstainers  20% 


Drinkers  Furnished  8O%  of  the   Cases 

70  Deaths  from  Sunstroke  1896 

Abstainers 
ffeavy  Drinkers  60%  Moderate   Drinkers  SO  %       /Q% 


Drinkers  Furnished  9O%  of  the  Cases 

Copyright,  1913,  by  Scientific  Temperance  Federation,  Boston,  Mass. 

FIG.  220.  —  Alcohol  and  Sunstroke.     Statistics  U.  S.  Weather  Review, 
November,  1896. 

heat  of  the  sun.  The  clothing  in  hot  weather  should  be 
light  and  loose.  Alcohol  in  any  form  lowers  the  resistance 
so  much  that  sunstroke  easily  occurs  in  persons  who  use  it 
(Fig.  220). 


Bacteria  and  Disease  383 

Electricity.  —  Great  electrical  plants,  used  in  industry, 
are  a  source  of  danger.  Individuals  should  not  go  near 
these  machines  unless  engaged  in  caring  for  them.  In  no 
case  should  one  enter  a  dynamo  *  room  with  wet  clothing. 
Electric  wires  and  connections  in  the  home  should  be  in- 
sulated and  repairs  should  always  be  made  by  an  electrician. 

Mountain  sickness.  —  When  coming  into  a  mountainous 
region  from  low  altitude,  care  should  be  taken  not  to  engage 
in  mountain  climbing  the  first  day.  Time  is  necessary  for 
adjustment  of  the  body  to  tjie  new  conditions.  Mountain 
climbing  should  be  engaged  in  only  by  the  vigorous  and 
strong. 

Caisson*  disease.  —  Men  who  work  underground  in  tunnels 
and  mines  in  an  air  of  high  pressure  suffer  cramps  and 
paralysis  on  emerging  into  the  air  above  ground  unless  the 
ascent  is  very  gradual.  Laws  in  some  states  compel  em- 
ployers to  control  this  change.  But  for  such  workers  it  is 
very  important  to  know  that  "  bad  physical  health,  diseases 
of  the  kidneys  or  heart,  alcoholism,  obesity,  and  hunger  are 
contraindications  *  for  subjecting  one's  self  to  the  high  at- 
mospheric pressure." 

Injury  of  the  body  by  chemical  agents.  —  Chemicals,  when 
brought  in  contact  with  the  skin,  may  burn  it,  and  when 
taken  into  the  system  they  injure  the  body  cells. 

Lead  poisoning.  —  Alcoholism  again  plays  a  prominent 
part  in  increasing  the  susceptibility  to  lead  poisoning. 
Lack  of  cleanliness  is  also  to  be  considered,  and  workers  in 
industries  where  lead  is  used  should  have  the  hands  clean 
when  food  is  eaten.  There  is  a  popular  tradition  among 
lead  workers  that  chewing  tobacco  is  a  preventive  of  the 
disease  but  this  is  not  so. 

The  most  dangerous  trades  connected  with  the  use  of 
lead  are,  lead  mining  and  smelting,  zinc  smelting,  working 
in  white  lead  and  lead  colors,  making  lead  pipes  and  other 
lead  objects,  type  making  and  type  setting,  and  working  in 


Healthful  Living 


electric  storage-battery  factories.  Painters  and  workers  in 
ceramics  and  rubber  goods  frequently  suffer  from  the  lead 
used  in  manufacture,  if  they  are  not  careful.  Cleanliness 


FIG.  221.  —  Mosquitoes.     Comparison  of  — 


The  non-malarial  Genus  Culex. 
Palpi  short. 
Wings  not  spotted. 
Legs  sometimes  spotted. 
Position  at  rest,  parallel  to  surface. 


Larva,  or  wiggle-tail,  breathes,  and 
rests  perpendicular  to  surface  of 
water. 


The  malarial  Genus  Anopheles. 
Palpi  long. 

Wings  sometimes  spotted. 
Legs- not  spotted. 
Position  at  rest  with  abdomen  and 

hind  legs  elevated  at  an  angle  to 

surface. 
Larva,  or   wiggle-tail,    is   parallel 

to    surface    of    water    when  it 

breathes. 


The  sucking  tube  and  feelers  are  long  in  both  genera.  The  long  palpi  of 
the  malarial  genus  furnish  an  infallible  sign.  The  palpi  are  found  on  each 
side  of  the  sucking  tube.  The  feelers  are  next  to  the  palpi. 


and  avoidance  of  alcohol  are  the  things  to  be  remembered 
by  these  workers. 

Other  poisonous  metals.  —  Mercury,  phosphorus,  tin,  cop- 
per, brass,  and  zinc  poisoning  occur  among  workers  with 
these  metals.  Pure  air  in  the  factory,  sanitary  floors  and 


Bacteria  and  Disease 


385 


windows,  cleanliness  in  the  worker,  avoidance  of  alcohol  — 
these  are  the  measures  for  prevention. 

Diseases  caused  by  mosquitoes.  —  It  has  been  learned 
that  the  mosquito  can  carry  parasites  *  in  the  salivary  glands 
and  inject  them  into  the  blood  of  man  with  its  sting. 

Malaria.  —  This  disease  is  caused  by  the  bite  of  a  par- 
ticular mosquito,  called  the  anopheles  (Fig.  221),  which  at 
some  time  before  has  bitten  a  person  having  malaria.  You 


a 


FIG.  222.  —  Reproduction  of  the  malaria  parasite  in  a  red  blood  cell, 
a,  entering  the  cell ;  b,  within  the  cell ;  c-h,  development  and  segmentation 
of  the  parasite ;  i,  rupture  of  red  cell  setting  young  parasites  free ;  j,  one  of 
them  entering  a  red  cell.  This  process  goes  on  with  continual  destruction 
of  the  red  blood  corpuscles  until  the  parasites  are  killed  by  medical  treat- 
ment. 

see  in  this  way  the  mosquito  transmits  the  disease.  Pre- 
vention aims,  therefore,  to  kill  mosquitoes  of  this  particular 
kind  and  to  prevent  the  mosquito  from  biting  a  person  having 
the  disease.  The  mosquito  breeds  in  water  and  so  the  breed- 
ing places  of  the  insect  should  be  destroyed.  Stagnant  pools 
and  swamps  are  covered  with  oil  which  kills  the  young. 
Empty  cans  on  rubbish  piles  should  be  buried  so  that  no 
water  can  collect  in  them.  Boy  scouts  may  do  a' "good 
turn  "  by  organizing  a  "  Mosquito  Day."  Mosquitoes  may 


386  Healthful  Living 

be  stunned  in  the  house  by  burning  fresh  leaves  of  eucalyptus 
or  pyrethrum  powder  and  then  killed  before  they  revive. 
Persons  in  malarial  regions  and  persons  suffering  from 
malaria  should  live  in  houses  that  are  well  screened. 

A  person  does  not  get  malaria 
from  bad  water,  food,  exposure  to 
sun,  night  air,  or  in  any  way 
except  by  the  bite  of  a  mosquito 
which  has  sucked  the  blood  of  a 
person  who  has  malaria.  The 
mosquito  serves  to  transmit  the 
parasites  which  cause  the  disease, 
and  they  are  transmitted  in  no 
other  way. 

FIG.  223.  —  Larva  of  a  culex  _T71         J  .,  ..  .      . 

mosquito.  When  a  mosquito,  which   has 

previously  bitten  a  person  having 

malaria,  bites  another  person,  the  parasites  are  conveyed 
into  the  blood  of  the  second  person.  These  parasites  enter 
the  red  blood  cells  and  develop  and  increase  in  number  as 
shown  in  Figure  222. 

The  female  mosquito  lays  her  eggs  on  the  surface  of  stag- 
nant or  still  water  and  in  a  few  days  these  hatch  into  larvse,* 
often  called  "  wigglers."  The  larvse  develop  into  pupse  and 
finally  into  mosquitoes.  All  stages  in  this  development 
occur  in  water.  The  larvse  of  anopheles  require  from  twelve 
to  sixteen  days  in  warm 
weather  to  mature.  These 
larvse  may  be  distinguished 

from  the  larvae  of  other  and  ^^^l^^tll^ 
harmless  mosquitoes  by  the 

position  they  take  in  the  water.  The  anopheles  live  at  the 
top  of  the  water  and  parallel  to  its  .surface  (Figs.  223,  224). 

The  anopheles  can  best  be  destroyed  by  getting  rid  of 
them  in  the  larval  stage.  All  brush  and  weeds  surrounding 
dwelling  houses  and  mosquito  breeding  places  should  be  cut 


Bacteria  and  Disease 


387 


down.  The  breeding  places  can  be  destroyed  by  draining, 
filling,  or  oiling.  By  draining  or  filling,  the  water  necessary 
for  the  deposit  of  eggs  is  removed  ;  by  oiling  the  water,  a 
thin  film  of  oil  is  formed  that  prevents  the  larvse  from  getting 
air  and  so  they  die.  If  oiling  is  the  method  chosen,  it  should 
be  done  every  fourteen  days. 

Yellow  fever.  —  This  disease  at  one  time  was  not  con- 
trollable because  it  was  not  known  how  the  infection  *  was 
carried.  Now  it  is  known  that  the  mosquito,  Stegomyia 
fasciata,  carries  the  disease.  The  preventive  measures  in 
malaria  apply  here. 

Tuberculosis.  —  As  the  tubercle  bacilli  (Fig.  225)  multiply 
in  the  body,  tiny  tubercles  are  formed ;  hence  the  name. 
Tubercles  are  growths  shaped  like  pin  heads,  and  they  may 
be  formed  in  any 
tissue  of  the  body. 
You  have  learned 
that  in  thousands 
of  cases  bacilli  in- 
jure a  part  of  a 
lung  and  it  heals 
over.  But  in 
thousands  of  cases 
the  individuals  have 
lived  wrong  physi- 
cally for  so  long,  and 
their  lungs  have  be- 
come so  weak,  that 
they  are  gradually 
destroyed  by  the 
bacilli. 


FIG.  225.  —  Tubercle  bacilli  in  sputum  of  a 
person  having  tuberculosis  of  the  lungs. 


Whether  the  body  has  been  injured  through  ignorance 
or  self-sacrifice,  through  dissipation  or  selfish  ambition  for 
money  or  fame,  through  foolish  attempts  at  beauty,  through 
devotion  to  learning,  or  through  some  unselfish  love  and 


388  Healthful  Living 

work  for  others,  the  result  is  the  same.;  nature  knows  no 
difference.  However  noble  the  character  or  wise  the  mind, 
when  a  vital  organ  has  sunk  in  health  below  the  standard 
necessary  for  a  human  being,  deterioration  comes. 

Bacilli  may  be  found  in  the  sputum  in  an  early  stage  of 
tuberculosis.  Then  recovery  is  more  difficult,  but  it  will 
often  come  if  the  person  returns  to  natural  ways,  living  out 
of  doors  and  allowing  the  forces  of  health  to  purify  the  body. 

Many  people  die  from  tuberculosis  and  yet  in  many  cases 
the  disease  would  not  occur  if  proper  care  had  been  exercised 
by  the  individual,  or  by  those  who  have  the  disease.  If  one 
who  has  the  disease  is  careless  and  distributes  the  germs 
and  if  those  who  have  not  the  disease  are  careless  in  matters 
of  hygiene,  there  exists  a  situation  which  makes  it  easy  for 
one  person  to  infect  many.  No  one  desires  this  to  occur. 
All  must  work  against  such  spreading  of  infection. 

Now  it  is  known  that  the  sun's  rays  destroy  the  bacillus 
of  tuberculosis.  A  man  by  the  name  of  Twitchell  found 
that  the  sputum  containing  tubercle  bacilli  exposed  to  direct 
sunlight  for  seven  hours,  could  not  produce  the  disease,  and 
the  same  sputum  kept  in  a  closed  darkened  bedroom  with 
carpeted  floor  and  heavy  hangings,  caused  the  disease  even 
after  thirty-nine  days.  Are  the  sun's  rays  valuable  ?  Should 
the  floor  be  covered  with  carpets  or  with  rugs  ? 

Children  from  earliest  infancy  should  be  accustomed  to 
fresh  air.  Babies  four  weeks  old  should  be  taken  out  of 
doors  and  even  newborn  babies  should  sleep  in  a  room  with 
the  window  open.  If  the  baby  at  home  is  bottle  fed,  the 
milk  used  should  be  from  cows  that  have  been  tested  by 
tuberculin  *  for  tuberculosis  and  the  milk  should  be  pas- 
teurized. Do  you  know  of  a  baby  living  on  cow's  milk?  Is 
the  milk  pure  ?  Is  the  milk  pasteurized  ? 

Prevention  of  communicable  diseases.  —  Many  of  the 
diseases  of  the  body  are  caused  by  the  germs  of  the  disease 
gaining  entrance  to  the  body.  If  the  entrance  can  be  pre- 


Bacteria  and  Disease  389 

vented,  the  disease  will  be  prevented.  In  addition,  the  body 
must  be  made  strong  and  healthy  so  that  the  germs  which 
break  through  the  blockade,  Health  Care,  will  be  destroyed 
by  the  forces  present  in  the  body.  To  prevent  the  entrance 
of  germs  we  should  consider  : 

Cleanliness  of  the  mouth.  —  The  teeth  must  be  kept  clean 
by  brushing  at  least  twice  daily.  All  cavities  must  be  filled. 

Drinking  water.  —  The  water  used  for  drinking  should  be 
pure.  Pure  drinking  water  is  tasteless,  odorless,  sparkling, 
without  organic  matter,  and  without  disease  germs. 

Clean  food.  —  Food  taken  into  the  body  to  build  our 
bodies  should  be  clean.  People  should  never  eat  at  dirty 
restaurants.  If  restaurants  were  chosen  on  the  basis  of 
cleanliness,  by  all  people,  there  would  not  be  any  dirty  ones 
left  —  they  would  have  to  "  clean  up  "  or  "  get  out."  Chil- 
dren in  the  cities  should  not  buy  food  from  street  venders 
who  expose  their  food  to  dust  and  dirt  and  flies. 

Care  of  the  bowels.  —  The  waste  of  the  body  must  be  re- 
moved daily  and  regularly.  The  best  time  for  this  elimina- 
tion to  occur  is  after  breakfast.  No  exception  to  this  habit 
should  ever  be  allowed. 

Bathing.  —  The  body  should  be  bathed  daily  in  certain 
parts,  and  the  entire  body  should  be  washed  at  least  once 
a  week.  A  shower  bath  is  the  most  sanitary  form  of  bath. 
Rural  schools  and  homes  without  running  water  can  arrange 
for  showers  by  providing  a  perforated  pail  suspended  so  that 
it  can  be  filled  and  can  distribute  the  water  in  a  spray!. 

Sleeping.  —  One  should  be  accustomed  to  fresh  air  and, 
therefore,  open  windows  at  night  are  very  important.  Even 
in  cold  weather  the  window  of  the  sleeping  room  should  be 
partly  open.  The  number  of  hours  of  sleep  which  children 
of  different  ages  should  have  are  given  on  page  325. 

Prevention  of  influenza.  —  The  very  serious  epidemic  of 
influenza  in  the  United  States  in  the  fall  of  1918,  caused 
more  deaths  in  the  army  and  civil  population  "  over  here  " 


39°  Healthful  Living 

than  were  caused  by  German  bullets  in  the  U.  S.  Army 
"over  there."  Jn  prevention  of  the  disease,  the  factors 
which  have  been  repeatedly  mentioned  as  important  hygienic 
practice,  are  the  ones  most  effective.  In  this  connection  it 
is  instructive  to  learn  the  memorandum  for  strengthening 
personal  resistance,  which  was  issued  September  27,  1918, 
by  the  Office  of  the  Surgeon-General,  U.  S.  A. 


"HOW    TO    STRENGTHEN    OUR    PERSONAL    DEFENSE 
AGAINST   SPANISH   INFLUENZA" 

1.  Avoid  needless  crowding  —  influenza  is  a  crowd  disease. 

2.  Smother  your  coughs  and  sneezes  —  others  do  npt  want  the 
germs  which  you  would  throw  away. 

3.  Your  nose,  not  your  mouth,  was  made  to  breathe  through 
—  get  the  habit. 

4.  Remember  the  three  C's  —  a  clean  mouth,  clean  skin,  and 
clean  clothes. 

5.  Try  to  keep  cool  when  you  walk  and  warm  when  you  ride 
and  sleep. 

6.  Open  the  windows  —  always  at  home  at  night ;    at  the 
office  when  practicable. 

7.  Food  will  win  the  war  if  you  give  it  a  chance  —  help  by 
choosing  and  chewing  your  food  well. 

8.  Your  fate  may  be  in  your  own  hands  —  wash  your  hands 
before  eating. 

9.  Don't  let  the  waste  products  of  digestion  accumulate  — 
drink  a  glass  or  two  of  water  on  getting  up. 

10.  Don't  use  a  napkin,  towel,  spoon,  fork,  glass  or  cup  which 
has  been  used  by  another  person  and  not  washed. 

11.  Avoid  tight  clothes,  tight  shoes,  tight  gloves  —  seek  to  make 
nature  your  ally,  not  your  prisoner. 

12.  When  the  air  is  pure  breathe  all  of  it  you  can  —  breathe 
deeply. 

CHARLES  RICHARD,  Brig.  Gen.  M.  C.,  Act.  Surg.-Gen.  U.S.A. 

It  will  be  seen  that  we  must  be  careful  to  keep  our  bodies 
so  strong  by  careful  living  that  no  germs  can  enter.  The 
following  table  shows  the  ways  and  means  of  infections  that 
are  common  and  important : 


Bacteria  and  Disease 


TABLE   OF    THE  WAYS   AND  MEANS  OF  COMMUNICATION   OF  THE 
IMPORTANT  INFECTIONS  OF  MAN 


DISEASE 

FROM 
CONTACT 

WITH   SlCK 

PERSON  OR 
ANIMAL 

FROM 
CONTACT 

WITH 

THINGS 
SICK  HAVE 
USED 

DRINKING 
WATER 

CAN 

CARRY 
THE  GERM 

FOOD 

CAN 

CARRY 

THE 

GERM 

AIR 

CAN 

CARRY 

THE 

GERM 

ANI- 
MALS 

CAN 

CARRY 

THE 

GERM 

INSECTS 
CAN  CARRT 
THE  GERM 

Anthrax  .     . 

yes 

yes 

yes 

yes 

cattle 

flies 

Cholera  .     . 

yes 

yes 

common 

yes 

flies 

way 

Diphtheria 

common 

bedding 

yes 

yes 

flies 

way 

etc. 

Erysipelas    . 

yes 

yes 

yes 

Influenza 

chief 

yes 

yes 

way 

Malaria  . 

mosquito 

only 

Measles  . 

common 

yes 

yes 

way 

Mumps   .     . 

yes 

yes 

yes 

Rabies  ,   ... 

only 

dogs 

way 

Scarlet    .     . 

common 

yes 

yes, 

yes, 

fever      .'   .. 

way 

milk 

skin 

Trachoma    . 

common 

yes, 

yes 

flies 

way 

towels, 

etc. 

Tubercu- 

yes 

yes 

yes, 

yes 

cattle 

flies 

losis       .     . 

milk 

Typhoid 

rarely 

yes 

common 

yes, 

flies 

fever      .     . 

way 

milk 

Wound 

infections 

such  as  cuts, 

boils,  etc.   . 

yes 

yes 

yes 

yes 

flies 

392 


Healthful  Living 


How   bacteria   are   destroyed   within  the   body.  —  If,   in 

spite  of  keeping  the  body  in  a  splendid  condition  of  health, 
virulent  bacteria  gain  an  entrance  to  the  body,  even  then  the 
body  is  often  able  to  defend  itself  successfully  by  the  fol- 
lowing forces  at  its  disposal : 

First  —  The  white  blood  cells  have  as  their  chief  function 
to  seek  out  bacteria  and  to  devour  and  destroy  them.  This 
explains  why  so  many  germs  are  necessary  to  transmit  a 
disease.  If  only  a  few  are  present,  these  cells  will  be  able 

to  protect  the  body.  If 
the  infection  is  too  great, 
or  if  the  infecting  bac- 
teria are  too  virulent, 
then  these  cells  may  fail 
(Fig.  226). 

Second  —  The    plasma 
of    the     blood     contains 
substances  which  are  able 
way   not    fully 


FIG.  226.  —  A,  germ  destroyed  by  white 
blood  cell ;  B,  cell  destroyed  by  germs 
and  the  germs  multiplying. 


in   some 

known     to     inhibit    the 
action  of  bacteria.    These 

substances  are  called  antibodies  *  and  are  developed  by  the 
body  during  the  course  of  the  infection.  Now  these  de- 
fenses are  dependent  in  a  very  definite  way  upon  the 
general  health  of  the  body  for  success.  The  action  of 
these  cells  is  more  pronounced  in  one  with  vigorous 
health.  It  has  never  been  proved  that  bacteria  will 
cause  disease  in  a  perfectly  healthy  body  and,  therefore, 
it  is  important  to  keep  the  body  in  a  fine  state  of  health, 
in  order  to  prevent  the  great  loss  occasioned  by  illness.  It 
is  perfectly  true  that  many  bacteria  seem  to  be  harmless 
under  certain  conditions,  but,  if  they  find  a  weakened  con- 
dition, they  seem  to  change  their  nature  and  begin  the  forma- 
tion of  poisonous  toxins.  Disease  occurs  then  in  a  large 
measure  because  people  do  not  care  for  themselves  properly. 


Bacteria  and  Disease  393 

How  bacteria  are  destroyed  outside  the  body. — The  sun  is 
the  great  destroyer  of  all  bacteria  in  summer  and  in  tropical 
climates.  Cold  destroys  them  in  winter  and  in  cold  climates. 
Wind  drives  away  bacteria.  It  is  almost  impossible  to  trans- 
mit disease  in  the  open  air.  Some  germs  feed  upon  other 
germs.  In  the  soil  are  certain  kinds  of  germs  which  oxidize 
all  organic  matter,  including  other  kinds  of  germs.  Thus 
germs  can  filter  through  only  a  few  feet  of  sand  before  they 
are  destroyed.  Well-water  is  safe  to  drink  if  no  impurities 
reach  the  soil  near  the  well,  but  where  the  ground  becomes 
soaked  with  germ-laden  sewage,  impurities  penetrate  farther 
and  well-water  is  unsafe. 

Cleaning  with  soap  and  water  removes  germs.  Drying 
kills  many  germs,  but  some  species  are  harder  to  kill  when 
dry ;  in  that  condition  they  will  stand  even  freezing.  Heat 
equal  to  that  of  boiling  water,  applied  for  15  minutes,  will 
kill  almost  every  kind  of  germ.  If  the  germs  are  killed  by 
a  boiling  temperature  it  does  no  harm  to  leave  air  in  the 
top  of  canned  vegetables  and  jars  of  preserves.  Milk  is  a 
nourishing  soil  for  germs  which  cause  stomach  trouble  with 
bottle-fed  babies,  unless  the  milk  has  been  pasteurized  and 
the  bottles  sterilized. 

Disinfection.  —  For  many  years  it  has  been  the  practice 
to  disinfect  the  rooms  of  people  recovering  from  communi- 
cable diseases,  such  as  measles  and  diphtheria.  The  idea  ex- 
pressed in  such  a  procedure  was  to  kill  the  germs  that  were 
in  the  room  inhabited  by  the  sick  person.  In  Providence, 
R.  L,  and  New  York  City  this  practice  has  been  abandoned 
and  health  officers  in  other  places  are  paying  more  attention 
to  cleanliness  by  soap  and  water.  It  is  true  that  any  article 
that  has  come  in  immediate  contact  with  the  sick  person, 
as  utensils,  books,  toys,  and  personal  articles,  should  be  dis- 
infected at  the  end  of  the  communicable  disease.  The 
danger  with  continuing  such  a  practice  as  terminal  disin- 
fection is  that  it  places  the  emphasis  in  the  wrong  place  and 


394  Healthful  Living 

makes  people  believe  that  the  danger  lies  in  the  room  and 
its  hangings.  The  danger  lies  in  coming  in  contact  with  the 
person  having  the  disease  and  allowing  that  person  to  cough 
or  breathe  in  your  face.  Doctors  and  nurses  generally  es- 
cape the  communicable  diseases  because  they  are  very  care- 
ful about  washing  their  hands  and  protecting  themselves  from 
coughs.  We  will  not  fear  infections  when  we  are  intelligent 
enough  to  avoid  the  real  dangers  and  do  not  allow  ourselves 
to  be  deluded  by  a  false  security. 

Antiseptics*  —  There  is  a  considerable  interest  to-day  in 
preventing  disease  and  many  people  are  impressed  with  the 
large  number  of  antiseptics  on  the  market.  Everything  on 
the  market  used  by  people  in  a  personal  way  claims  some 
particular  antiseptic  feature.  Tooth  powders,  shaving  soap, 
gargles,  and  numerous  other  articles  claim  this  feature. 
Now,  the  important  thing  for  us  to  remember  is  that  the 
antiseptic  day  has  passed  and  we  are  living  in  an  age  that  is 
emphasizing  the  aseptic  feature  in  both  sanitation  and  surgery. 
Surgeons  do  not  employ  antiseptics  as  formerly  in  the  care  of 
wounds ;  they  use  aseptic  measures  and  keep  the  wound 
clean.  It  is  true  that  badly  infected  war  wounds  are  treated 
to-day  by  a  new  and  powerful  antiseptic,  known  as  the  Carrel- 
Dakin  solution,  but  sanitarians  to-day  depend  upon  cleanli- 
ness and  isolation  of  the  sick  person,  and  pay  scant  attention 
to  antiseptics  and  disinfectants.  The  modern  method  in 
housekeeping  is  to  keep  the  house  clean  and  avoid  the  spring 
house  cleaning;  the  modern  method  in  disease  prevention 
is  to  keep  the  sick  isolated  from  the  well,  to  keep  the  sick 
and  the  well  clean,  and  not  try  to  kill  the  germs  after  dirty 
habits  of  living  have  allowed  severe  infections  to  occur. 

A  curious  theory  of  disease.  —  There  is  an  artless  theory, 
common  among  unlettered  people,  which  holds  that  disease 
is  a  distinct  thing,  and  that  when  God  made  the  various 
diseases,  he  made  plants  to  grow,  each  of  which  contains  the 
infallible  remedy  for  one  of  the  diseases.  Such  persons  when 


Bacteria  and  Disease  395 

they  are  ill,  and  after  various  treatments  remain  ill,  cherish 
the  firm  conviction  that  if  they  could  only  find  the  right 
remedy  that  is  growing  in  some  plant,  somewhere  in  the 
world,  they  would  immediately  be  cured,  without  any  at- 
tention to  hygiene  and  the  conditions  necessary  to  health 
and  its  recovery.  Patent  medicine  venders  particularly 
foster  this  idea,  although  each  one  illogically  adds  that  his 
medicine  will  cure  all  diseases  indiscriminately. 

This  simple  theory  is  opposed  to  all  the  facts.  The  poisons 
in  plants  are  waste  products  that  the  plant  seeks  to  remove. 
They  are,  therefore,  found  mostly  in  the  parts  of  the  plant 
that  will  be  shed,  as  the  leaves,  seeds,  and  bark.  The  poisons 
serve  meanwhile  to  protect  the  plant  from  animals.  The 
only  animals  (besides  man)  that  will  touch  the  tobacco  plant 
are  the  goat  and  the  tobacco  worm ;  their  bodies  seem  to 
have  become  used  to  the  poison.  No  sick  cat  eats  night- 
shade, no  sick  cow  eats  jimson  weed.  The  very  bitter  or 
repulsive  taste  of  most  poisons  shows  them  to  be  unsuited 
to  the  animal  body.  No  child  would  drink  a  liquid  con- 
taining the  bitter  alkaloid,*  caffeine,*  unless  it  were  in- 
fluenced by  the  example  of  its  elders,  and  the  bitter  taste 
were  disguised  with  milk  and  sugar. 


HEALTH   RULES   FOR   SCHOOL   CHILDREN 

(From  Public  Health  News,  State  Department  of  Health,  New 

Jersey.) 

The  "  DO  "  Rules,  or  What  to  Do  to  Prevent  Disease 

1.  Keep  away  from  houses  where  any  one  is  sick  with  infantile 
paralysis  or  other  communicable  disease. 

2.  Keep  away  from  sick  people  and  those  who  have  been  in 
contact  with  sick  people. 

3.  During  an  epidemic,  keep  away  from  crowds. 

4.  Destroy  all  discharges  from  the  nose  and  mouth. 


396  Healthful  Living 

5.  Always  cover  your  mouth  with  a  handkerchief  when  you 
cough  or  sneeze.     If  you  cannot  get  a  handkerchief,  use  your  hands 
and  then  wash  them  at  once. 

6.  Keep  away  from  flies  and  keep  flies  away  from  you.     Flies 
carry  germs  on  their  feet  and  in  their  stomachs. 

7.  Wash  your  hands  with  soap  and  water  upon  rising  in  the 
morning,  before  each  meal,   after  each  visit  to  the  toilet,   after 
coughing  or  sneezing  in  the  hand,  and  before  going  to  bed. 

8.  Keep  clean.     Take  a  bath  every  day  and.  see  that  all  cloth- 
ing worn  next  to  the  skin  is  clean. 

9.  Kill  all  vermin  such  as  bedbugs,  roaches,  and  body  lice. 

10.  Keep  your  books,  your  pencils,  and  your  desk  clean. 

11.  Eat  plain,  wholesome  food,  including  plenty  of  milk  and 
vegetables. 

12.  Keep  the  milk  clean,  covered,  and  cold. 

13.  Protect  all  food  from  flies. 

14.  Wash  all  food  that  is  to  be  eaten  raw., 

15.  Keep  down  dust.     Always  sprinkle  floors  with   sawdust, 
old  tea  leaves,  or  bits  of  newspaper,  which  have  been  thoroughly 
dampened,  before  sweeping.     Never  allow  dry  sweeping. 

16.  Brush  your  teeth  daily,  or  better,  twice  a  day. 

The  "  DO  NOT  "  Rules,  or  What  to  Avoid  to  Prevent  Disease 

1.  Do  not  go  near  sick  people  or  the  houses  where  they  live. 

2.  Do  not  go  in  crowds  during  an  epidemic. 

3.  Do  not  kiss  anybody  on  the  mouth,  and  do  not  let  any- 
body kiss  you  on  the  mouth. 

4.  Do  not  cough  or  sneeze  in  anybody's  face  or  over  food. 

5.  Do  not  put  your  fingers  or  pencils  in  your  mouth  or  nose. 

6.  Do  not  spit  or  blow  your  nose  on  the  floor  —  use  a  hand- 
kerchief. 

7.  Do  not  bite  the  corners  of  your  books. 

8.  Do  not  spit  on  your  hands  when  you  play  ball. 

9.  Do  not  bite  an  apple,  candy,  or  other  food  that  some  one 
else  has  been  eating. 

10.  Do  not  eat  food  that  flies  have  walked  over. 

11.  Do  not  eat  with  dirty  hands  —  wash  them. 

12.  Do  not  eat  with  your  fingers  —  use  a  fork  or  spoon. 

13.  Do  not  handle  foods  that  others  are  to  eat  unless  your 
hands  are  absolutely  clean. 

14.  Do  not  eat  foods  that  have  been  handled  by  unclean  hands. 


Bacteria  and  Disease  397 

15.  Do  not  eat  apples,  pears,  or  other  raw  fruits  from  the  market 
until  they  are  carefully  washed. 

16.  Do  not  stir  up  the  dust  either  at  home  or  at  school. 

17.  Do  not  drink  out  of  a  cup  that  other  people  have  used. 

18.  Do  not  wipe  on  a  towel  used  by  any  one  else. 

19.  Do  not  lend  your  pencils  or  books  to  others. 

20.  Do  not  borrow  books  or  pencils,  but  have  your  own  and 
keep  them  for  your  own  use. 

21.  Do  not  trade  chewing  gum,  candy,  horns,  or  whistles. 

22.  Do  not  wipe  your  nose  on  your  hand  or  sleeve  —  use  a 
handkerchief. 

23.  Do  not  use  a  soiled  handkerchief  —  get  a  clean  one. 

24.  Do  not  wet  your  finger  on  your  tongue  to  turn  the  leaves 
of  a  book. 

25.  Do  not  have  dirty  hands  —  wash  them. 

GLOSSARY 

Alkaloid.  —  An  organic  base  containing  nitrogen,  (a  base  is  a 
compound  capable  of  uniting  with  an  acid  and  forming  a  salt), 
and  having  powerful  poisonous  effect  upon  the  animal  body. 
Alkaloids  are  of  vegetable  origin. 

Antibodies.  —  Substances  developed  in  the  blood  during  the  course 
of  a  disease.  They  are  the  chemical  factors  in  the  immunity 
conferred  by  the  disease. 

Antiseptic.  —  Preventing  fermentation  and  decomposition.  Pre- 
venting the  growth  of  bacteria. 

Antitoxin.  —  A  serum  for  the  treatment  of  diphtheria.  It  is  made 
by  injecting  Bacillus  diphtheria  in  a  horse  and  after  the  horse 
has  developed  the  antibodies  of  immunity,  the  serum  of  the 
blood  of  the  horse  is  taken  and  certain  graduated  amounts 
used  in  treating  diphtheria  in  man. 

Caffeine.  —  An  alkaloid  found  in  coffee. 

Caisson.  —  A  large  water-tight  box  in  which  work  is  done  below 
the  water  level.  The  pressure  of  the  air  in  a  caisson  is  higher 
than  in  ordinary  atmosphere. 

Cholera.  —  An  acute  epidemic  disease  caused  by  the  Bacillus  of 
Koch,  a  comma-shaped  bacillus. 

Contraindication.  —  A  sign  or  symptom  indicating  the  inappro- 
priateness  of  the  procedure. 

Dynamo.  —  A  machine  driven  by  steam  or  some  other  force  which 
converts  the  energy  of  the  machine  into  electrical  energy  in 
the  form  of  an  electric  current. 


Healthful  Living 

Fungus.  —  A  plant  without  chlorophyll  that  derives  its  nourish- 
ment entirely  from  organic  compounds.  It  will  be  remembered 
that  plants  having  chlorophyll  obtain  their  nourishment  by 
using  inorganic  compounds. 

Immunity.  —  A  condition  developed  in  the  body  either  actively 
by  the  individual  or  passively  by  an  operator.  Active  immunity 
results  in  the  course  of  a  disease  by  the  formation  of  anti- 
bodies in  the  blood.  Passive  immunity  is  developed  by  in- 
jecting into  the  blood  an  immune  serum  such  as  antitoxin, 
or  by  such  a  process  as  vaccination. 

Infection.  —  A  condition  developed  in  the  body  by  the  entrance 
of  disease-producing  organisms  into  the  body. 

La  Grippe.  —  An  acute  epidemic  disease  caused  by  the  Bacillus 
influenzce.  It  is  easily  communicable  and  should  be  avoided. 

Larva.  —  One  of  the  forms  of  an  animal  after  leaving  the  egg 
form  and  before  it  appears  like  the  parent.  This  type  of  de- 
velopment is  seen  especially  in  insects. 

Lockjaw.  —  The  popular  name  for  a  disease  that  shows  by  an  early 
affection  of  the  jaw  muscles.  The  disease,  tetanus,  is  caused 
by  the  Bacillus  tetani.  This  organism  is  prevalent  in  soil 
especially  around  barnyards  and  richly  fertilized  fields. 

Microbe.  —  A  name  sometimes  used  for  bacterium  or  germ. 

Mold.  —  A  fungous  growth  occurring  in  warm  moist  places  and 
seen  especially  on  food,  walls,  and  clothing. 

Obesity.  —  A  condition  of  great  fatness  with  accompanying  un- 
soundness. 

Parasite.  —  A  living  organism  that  lives  on  or  in  another,  called 
its  host,  from  which  the  parasite  derives  its  nourishment. 

Pasteurize.  —  To  heat  milk  to  a  temperature  from  150°  to  155°  F. 
for  twenty  to  thirty  minutes,  for  the  purpose  of  destroying 
the  bacteria  of  the  milk.  This  method  was  originally  proposed 
by  Pasteur,  a  great  French  scientist. 

Plague.  —  A  pestilence  or  severe  epidemic  disease.  In  the  middle 
ages  plagues  were  common.  To-day  they  are  less  common 
because  we  know  the  causes  of  them  and  how  to  combat  their 
spread. 

Ptomaine.  —  A  poison  developed  in  food  by  a  process  of  fermenta- 
tion and  decomposition. 

Quarantine.  —  Preventing  for  a  fixed  period  of  time  (originally 
forty  days,  quadraginta,  forty)  communication  with  persons, 
'ships,  or  goods  arriving  from  ports  infected  with  communi- 
cable disease. 


Bacteria  and  Disease  399 

Serum.  —  The  plasma  of  the  blood  is  called  the  serum,  but  the 
term  is  also  used  to  designate  the  material  used  for  immuniz- 
ing purposes.  Antitoxin  is  a  serum  and  is  made  from  the 
plasma  of  a  horse. 

Sterilize.  —  To  make  sterile,  without  life.  By  a  process  of  heat 
or  chemicals  to  destroy  all  the  bacterial  life  on  an  instrument, 
gauze,  etc. 

Toxin.  —  The  poison  developed  by  bacteria. 

Tuberculin.  —  A  liquid  prepared  by  growing  Bacillus  tuberculosis 
in  a  broth  culture. 

Vaccination.  —  A  process  of  developing  in  man  immunity  to  small- 
pox by  causing  a  mild  form  of  the  disease  when  the  small- 
pox virus  is  rubbed  into  a  small  opening  in  the  skin  of  the  arm 
or  leg. 

Vaccine.  —  A  preparation  of  the  weakened  or  the  dead  bodies  of 
bacilli  used  to  inject  into  man  for  the  purpose  of  developing 
immunity  to  a  particular  disease. 


CHAPTER   XX 
THE    EFFECT    OF    ALCOHOL    AND    TOBACCO 

I.    The  Body  as  a  Storehouse  of  Energy. 
II.    The  Meaning  of  Fatigue. 

III.  The  Effect  of  Stimulants  on  Energy  and  Nerves. 

Artificial  stimulants 
Natural  stimulants 

IV.  Alcohol. 

As  a  food 
As  a  poison 

Summary  of  the  effects  of  alcohol 
V.   Tobacco. 

General  effects  of  tobacco 

The  effects  of  tobacco  upon  youth 


The  body  as  a  storehouse  of  energy.  —  Succi,  an  Italian, 
successfully  accomplished  a  fast  of  fifty  days  in  London,  be- 
ing constantly  watched  to  make  sure  of  his  fasting.  There 
is  reported,  on  good  authority,  a  case  of  an  insane  person 
who  suddenly  became  possessed  by  the  idea  of  taking  no 
food,  and  who  lived,  sixty  days  before  starving  to  death. 
Long  fasts  are  a  great  injury  to  the  body,  no  doubt,  but 
what  can  be  learned  from  such  experiences?  Certainly  it 
shows  the  wisdom  with  which  we  are  made  and  that  our 
physical  organization  is  very  provident. 

Once  some  miners  were  shut  in  by  caving  of  part  of  the 
mine.  But  unlike  the  cases  mentioned  above  they  were 
without  water  as  well  as  food.  When,  by  digging,  the 
rescuers  reached  them,  seven  days  after,  several  were  still 

400 


The  Effect  of  Alcohol  and  Tobacco  401 

found  alive,  although  most  of  them  had  succumbed.  The 
miners,  no  doubt,  had  nourishment  in -their  bodies  for  some 
weeks  more  of  life,  but  the  necessary  solvent  in  the  form  of 
water  was  lacking  to  dissolve  it  and  bring  it  within  the  reach 
of  the  cells  most  needing  it. 

This  fact  concerning  the  amount  of  nourishment  stored 
in  the  human  body  (in  one  case  a  two  months'  supply  !)  is 
one  of  the  most  stupendous  facts  with  which  the  science  of 
physiology  has  to  deal,  and  it  should  be  borne  in  mind,  or 
we  may  greatly  deceive  ourselves  about  some  very  simple 
matters.  Did  you  ever  get  so  tired  that  you  had  to  give  up 
and  stop,  however  much  you  would  have  liked  to  continue 
at  work  or  play?  To  rest  was  the  wise  thing  to  do.  Now, 
although  you  learn  from  physiology  how  much  energy  you 
have  stored  up  within  your  frame,  you  should  not  on  that 
account,  be  tempted  to  go  on  until  you  almost  break  down. 
Probably  you  know  people  who  are  conceited  about  their 
bodies  and  say  they  are  made  of  cast  iron ;  nothing  can  hurt 
them.  Did  you  ever  know  anybody  who  was  conceited 
about  his  mind  and  thought  he  was  very  bright?  It  is  just 
as  foolish  to  be  conceited  about  the  body.  It  is  a  very  wise 
arrangement  that  under  ordinary  conditions  we  cannot  get 
at  the  surplus  energy  we  have.  We  are  compelled  to  be 
provident,  as  it  were  ;  yet  stimulants  and  narcotics,  by  irri- 
tating the  cells,  will  cause  them  to  expend  some  of  this  re- 
serve energy ;  they  will  enable  man  to  get  at  this  precious 
store  which  he  should  save  for  emergencies,  such  as  a  period 
of  sickness  when  he  cannot  digest  food,  or  some  time  when  he 
is  making  some  mighty  effort.  This  reserve  energy  will 
enable  him  to  undergo  some  trying  ordeal  successfully.  Did 
you  ever  know  of  a  weak,  sick  man  who  had  eaten  very  little 
for  weeks,  yet  was  so  powerful  that  it  took  several  strong 
men  to  hold  him?  This  sometimes  happens  in  the  case  of 
sick  men  who  are  delirious  and  crazed  with  pain  and  with  the 
poisons  formed  in  their  bodies  during  illness. 

2D 


402  Healthful  Living 

The  meaning  of  fatigue.  —  Suppose  you  are  tired  or  worked 
out.  The  fatigue  depresses  you,  and  you  feel  discouraged. 
What  ought  you  to  do?  Why,  rest,  of  course,  and  you  will 
soon  feel  all  right  again.  This  seems  very  simple,  yet  some 
people  will  not  do  this  way,  but  take  an  alcoholic  beverage 
or  tobacco,  which  will  keep  them  from  feeling  tired  when 
they  are  tired.  If  you  have  been  working  hard  preparing 
for  examinations,  or  gathering  hay,  or  attending  to  some 
important  business,  or  have  been  under  the  excitement  of 
some  pleasure  trip,  and  feel  blue  and  worn  out,  then  bear 
the  result  like  a  man,  or  like  a  true  boy  or  girl,  as  the  case 
may  be.  Giving  up  for  a  while,  or  "  toughing  it  out  "  with 
the  blues,  or  losing  a  little  time  from  business,  will  not  hurt 
you  but  will  make  you  strong,  while  a  stimulant  would  leave 
you  less  of  a  man  than  before. 

There  is  only  one  source  of  energy  for  man's  body,  and 
that  is  the  union  of  food  and  oxygen.  He  must  get  his 
energy  from  the  same  source  that  the  engine  does,  and  that 
is  from  his  food,  which  serves  as  fuel,  and  the  oxygen  that 
burns  it.  The  millions  of  little  workers,  the  cells,  will  store 
up  food  within  themselves  and  get  rid  of  the  ashes  and  refuse, 
and  the  pure,  sound  body  will  be  ready  for  work  again. 

The  effect  of  stimulants  on  energy  and  nerves.  Artificial 
stimulants.  —  You  remember  those  wonderful  little  one- 
celled  animals,  the  amcebas.  If  poison  is  brought  near,  they 
will  try  to  escape  it.  They  also  throw  out  the  impurities 
generated  by  their  own  life  processes.  If  anything  touches 
one  roughly,  it  will  draw  back  from  the  danger.  Likewise, 
if  a  man  takes  poison,  such  as  alcohol  or  tobacco,  into  his 
body,  the  cells  will  try  to  throw  it  off.  The  heart,  although 
it  may  be  already  tired,  goes  to  thumping  anew,  secretions 
are  poured  out  by  the  cells  to  dilute  and  weaken  the  poison, 
and  the  great  activity  excited  diverts  the  man  from  noticing 
his  fatigue,  and  makes  him  think  the  poison  has  given  him 
renewed  strength.  It  is  the  same  as  if  he,  thought  the  whip 


The  Effect  of  Alcohol  and  Tobacco  403 

instead  of  the  oats  gave  the  horse  strength.  The  horse, 
like  the  cells  of  the  body,  is  only  trying  to  avoid  something 
harmful,  and  like  them,  he  uses  up  his  strength  in  so  doing. 
After  a  while  he  will  be  very  stiff  and  tired.  There  is  no 
artificial  stimulant  that  does  not  cause  a  reaction.  The 
stronger  the  stimulant,  the  worse  the  poison.  Strychnin* 
is  one  of  the  deadliest  poisons  known,  and  also  one  of  the 
most  powerful  stimulants.  If  an  animal  is  given  strych- 
nin, its  nerve  tissue  is  sometimes  reduced  to  such  an  irri- 
table condition  that  a  loud  sound,  or  merely  touching  any 
part  of  it,  will  throw  every  muscle  of  its  body  into  a  spasm. 

Some  people  are  coffee  topers  and  tea  topers.  It  is  a  mis- 
take to  say  these  drinks  quiet  the  nerves.  Who  is  so  nervous 
as  the  old  lady  who  drinks  frequent  cups  of  tea  to  quiet  her 
nerves?  It  is  the  tea  that  is  making  her  nerves  unsteady. 
Some  people  unaccustomed  to  tea  will  lie  awake  most  of  the 
night,  wearing  out  their  energies  by  sleeplessness  if  they 
drink  only  one  cup  of  it. 

It  is  easy  to  understand  how  a  person  sitting  up  with  a 
friend  who  is  dangerously  ill  will  take  tea  or  coffee  to  keep 
him  wide  awake.  If  he  has  some  great  duty  to  perform,  or 
trust  imposed  upon  him  that  will  soon  be  over,  there  may 
possibly  be  some  reason  in  stimulating  his  activities,  even  if 
he  must  suffer  reaction  and  depression  thereafter.  But  why 
one  will  habitually  disturb  his  body  with  narcotics,  such  as 
alcohol,  tobacco,  or  even  mild  narcotics,  such  as  tea  and 
coffee,  so  as  always  to  keep  his  vital  force  and  reserve  energy 
at  a  low  ebb,  is  difficult  to  understand.  It  can  only  be  ex- 
plained by  ignorance  of  the  fundamental  laws  of  his  being. 

Natural  stimulants.  —  The  chief  natural-  stimulants  are 
cold  air,  sunlight,  pure  air,  physical  exercise,  interest,  joy, 
and  other  wholesome  emotions.  A  deep  breath  of  pure  air 
is  a  better  stimulant  than  a  glass  of  beer ;  climbing  a  hill  or 
sawing  a  log  of  wood  will  make  the  blood  flow  faster  than 
an  alcoholic  drink  will ;  a  pleasant  talk  with  a  friend  is  a 


404  Healthful  Living 

better  sedative*  than  a  cigar;  a  cold  day  will  steady  the 
nerves  better  than  an  opiate* ;  a  trust  that  a  good  Power 
rules  over  all  will  drive  away  worry  quicker  than  cocaine ; 
a  cold  bath  will  bring  steadier  nerves  than  coffee ;  'a  cold 
wind  will  give  a  better  appetite  than  food  soured  with 
vinegar  or  hot  with  pepper.  Natural  stimulants  do  not 
produce  a  reaction  because  they  do  not  excite  the  body  to 
an  injurious  degree,  nor  cause  the  energies  to  be  consumed 
beyond  the  danger  point.  Persons  who  go  through  life  under 
the  stimulus  of  these  natural  blessings  have  sound  steady 
nerves  and  clear  brains.  They  do  not  have  to  take  anything 
"  to  quiet  their  nerves." 

Man's  body  was  beneficently  designed  to  keep  a  large 
amount  of  energy  stored  up,  so  that  he  can  feel  conscious 
of  his  power  and  go  through  life  buoyantly  and  happily, 
and  prepared  for  all  emergencies,  —  the  highest  being  in 
the  world  that  he  inhabits.  He  is  in  a  world  full  of  interest. 
Delicious  fruits  and  nutritious  nuts  and  grains  abound  to 
awaken  and  satisfy  his  appetite.  The  bright  sun  not  only 
shines  upon  his  skin,  but  deep  into  it,  and  stimulates  the 
cells;  the  fresh  breezes  striking  his  nerves,  start  currents 
coursing  through  his  body.  The  oxygen  penetrates  to  every 
cell,  purifying  and  awakening  to  life.  The  pleasure  of  as- 
sociation with  his  fellow-creatures,  and  various  other  pleas- 
ures, arouse  him  to  do  his  part  in  the  world.  There  is  no 
need  to  seek  in  the  jungle  for  some  bitter  berry,  or  among 
the  weeds  for  some  nauseating  leaf,  or  among  decaying  apples 
or  grapes  or  fermenting  grain  for  a  burning  and  revolting 
liquid  in  order  to  stir  his  being  to  action.  He  lives  the  life 
for  which  his  body  was  designed. 

Alcohol.  —  In  1914,  during  the  progress  of  the  Great  War, 
Russia  prohibited  the  manufacture  and  sale  of  vodka,  the 
alcoholic  drink  in  general  use  in  Russia  before  that  time. 
The  effect  upon  the  people  of  this  forced  abstinence  was  re- 
markable. Savings  banks  sprung  up  in  every  village  where 


The  Effect  of  Alcohol  and  Tobacco  405 

before  poverty  was  predominant ;  efficiency  in  all  phases  of 
Russian  life  increased;  and  the  nation  by  this  act  alone 
played  a  more  important  part  in  the  war  than  would  ha,ve 
been  possible  otherwise.  The  question,  "  Is  alcohol  a  food  ?" 
was  answered  by  the  Russian  in  terms  of  greater  national 
efficiency  by  the  removal  of  alcohol  from  the  diet. 

After  a  rapid  increase  in  prohibition  in  the  United  States, 
Congress  in  1917  passed  an  amendment  to  the  Constitution 
submitting  the  question  of  national  prohibition  to  the  state 
legislatures.  By  1919,  forty-five  state  legislatures  had  rati- 
fied the  amendment.  The  most  important  argument  for 
national  prohibition  has  been  the  argument  to  conserve  the 
food  of  the  country,  because  in  the  manufacture  of  alcohol  es- 
sential grains  of  the  food  supply  are  used  in  large  quantities. 
There  has  been,  also,  an  increasing  appreciation  of  the  loss  in 
efficiency  in  those  who  use  beer  and  whisky,  and  with  the 
whole  nation  training  to  become  efficient,  the  use  of  alcohol 
has  been  cast  aside  as  an  unnecessary  incubus. 

There  are  some  people,  however,  who  believe  that  alcohol 
is  a  food.  They  seek  to  justify  its  use  on  this  ground. 

Alcohol  as  a  food.  —  When  alcohol  is  taken,  about  ninety- 
five  per  cent  of  it  is  oxidized  and  changed  into  carbon  dioxide 
and  water.  This  was  found  out  many  years  ago  and  raised 
the  question  as  to  whether  it  should  be  classed  as  a  food. 
Investigations  were  made,  and  the  result  was  that  alcohol 
was  classed  with  the  poisons  and  not  as  a  food.  The  ques- 
tion has  been  reopened  several  times  in  the  last  half-century, 
but  always  with  the  same  result.  Scientific  men  generally 
continue  to  classify  it  as  a  poison  and  not  as  a  food.  Mor- 
phine, mushroom  poison,  strychnin,  and  other  dangerous 
poisons  are  oxidized  in  the  body  and  yield  up  their  energy, 
yet  they  are  recognized  as  poisons.  A  substance  cannot  be 
classified  as  a  food  simply  because  it  is  oxidized  in  the 
body. 

Leading  scientists  define  a  food  as  a  substance  of  such  a 


406  Healthful  Living 

nature  that,  when  absorbed  into  the  blood,  it  nourishes  the 
body  without  injuring  it. 

Sugar  is  a  food,  but  a  solution  of  sugar  can  undergo  a  change 
caused  by  the  growth  of  millions  of  yeast  plants  and  the  food 
is  lost.  The  change  is  called  fermentation,  and  alcohol  is 
one  of  the  poisonous  products  of  this  process  of  decay  or 
fermentation. 

The  condition  of  the  body  after  it  has  oxidized  alcohol 
is  quite  different  from  its  condition  after  it  has  oxidized 
sugar  or  bread.  Benzine*  is  very  easily  oxidized.  If  poured 
upon  the  fire  of  a  locomotive,  it  would  make  the  water  boil 
so  rapidly  that  there  would  be  danger  of  straining  or  bursting 
the  boiler.  It  would  burn  so  rapidly  as  almost  to  make  an 
explosion,  and  a  very  large  part  of  the  heat  caused  by  the 
oxidation  would  be  lost.  A  stove  needs  a  slower  burning 
substance  than  gunpowder  or  benzine.  A  locomotive  needs 
a  slow-burning  fuel  which  will  develop  heat  at  such  a  rate 
that  it  will  be  possible  to  utilize  it.  The  body  needs  even 
slower  burning  substances  than  the  locomotive,  sugar,  starch, 
and  fat;  not  a  more  rapidly  burning  substance,  such  as 
alcohol,  which  in  burning  will  weaken  the  tissues  and  shock 
and  injure  the  delicate  cells  of  the  one  who  drinks  it.  In  the 
chapter  on  the  blood  it  was  learned  that  alcohol  does  not 
even  cause  a  gain  of  heat  in  the  end,  since  the  paralysis  of 
the  capillaries  resulting  from  a  drink  causes  the  warmth  to 
be  taken  to  the  surface  and  escape,  so  that  the  body  is  cooler 
than  before  the  drink. 

True  food  does  not  burn  in  the  blood ;  it  is  stored  in  the 
cells  in  the  form  of  very  unstable  compounds.  These  com- 
pounds break  down  under  the  stimulus  of  oxygen  and  the 
nerve  impulse,  and  set  free  energy.  The  cells  of  the  nerves 
and  muscles  correspond  to  the  furnace  and  steam  chest  of 
the  engine.  Suppose,  instead  of  pouring  benzine  into  the 
furnace,  you  burned  it  in  the  cab  or  the  smokestack.  Do 
you  think  it  would  increase  the  power  of  the  locomotive? 


The  Effect  of  Alcohol  and  Tobacco  407 

Alcohol  is  not  stored  in  the  cells,  nor  does  it  enter  into  com- 
bination to  form  the  energy  compound,  the  breaking  down 
of  which  sets  free  the  energy  stored  up.  Alcohol  burns 
quickly  after  entering  the  body ;  a  large  part  of  it,  indeed, 
never  gets  beyond  the  liver,  and  is  burnt  in  this  long-suffer- 
ing organ.  But  some  of  it  gets  into  the  general  circulation, 
and  is  distributed  throughout  the  body,  irritating  the  nerve 
cells  and  poisoning  them  and  every  other  tissue. 

Alcohol  may  not  be  considered  a  food,  therefore,  because 
it  is  not  a  tissue  builder,  as  are  the  proteins,  and  it  is  not 
stored  in  the  body,  as  are  the  fats.  In  addition,  since  it  has 
a  toxic  action,  it  injures  the  body  when  taken  in  excess. 
This  may  be  the  case  with  other  foods,  but  they  give  warn- 
ing when  taken  in  excess.  Alcohol  as  a  food  is  exceedingly 
expensive.  Dr.  Woods  Hutchinson  has  said,  "  as  a  food, 
alcohol  is  a  joke  and  a  bad  joke  at  that." 

Dr.  D.  B.  Armstrong  gives  the  following  figures  in  tabular 
form  to  indicate  just  how  expensive  alcohol  as  a  food  would 
be  (food  is  useful  to  the  body  primarily  as  it  gives  energy, 
and  its  power  to  produce  energy  is  dependent  upon  its  caloric 
value) . 

APPROXIMATE  FOOD  VALUE  FOR  TEN  CENTS 

CALORIES  FOB 
ARTICLE  TEN  CENTS 

Sherry 30 

Beer         240 

Sirloin  Steak 375 

Eggs        450 

Bread .  2180 

Corn  meal         3310 

Oatmeal 3720 

Alcohol  as  a  poison.  —  C.  F.  Hodge,  Professor  of  Physi- 
ology in  Clark  University,  made  a  series  of  experiments  upon 
four  kittens  and  four  spaniels.  Moderate  non-intoxicant 
doses  of  alcohol  were  given  daily  to  two  of  each.  The  purring 


408  Healthful  Living 

and  playfulness  of  the  kittens  dosed  with  alcohol  gradually 
disappeared.  At  the  end  of  ten  days,  they  took  severe 
colds.  They  were  dwarfed  in  growth  to  59,  63,  and  39  per 
cent,  respectively,  as  compared  with  the  others.  Of  the 
two  pairs  of  spaniels,  the  pair  treated  with  alcohol  weighed 
less,  and  developed  only  71  and  57  per  cent  of  the  activity 
of  the  other  pair,  as  shown  by  the  pedometer.  The  dogs 
treated  with  alcohol  also  developed  strange  symptoms  of 
timidity  and  fear,  suggesting  the  terrible  fears  of  delirium 
tremens  and  alcoholic  insanity. 

Decreased  Physical  Efficiency.  —  In  Dr.  Hodge's  opinion 
the  experiments  above  described  have  direct  bearing  on  the 
question  of  the  effect  of  alcohol  on  the  human  system.  The 
experiments  proved  that  alcohol  causes  depression  of  activity. 
For  man  the  highest  aim  is  to  develop  useful  activity,  the 
will,  the  determination  to  do  as  much  of  the  world's  necessary 
work  as  he  is  capable  of  doing,  and  to  maintain  a  sound, 
vigorous  body  to  enable  him  to  carry  out  such  determina- 
tion. It  is  of  the  utmost  importance,  therefore,  that  we 
understand  the  conditions  of  our  physical  systems  under 
which  this  great  end  can  best  be  attained. 

General  Wolseley,  of  the  British  Army,  found  on  experi- 
ment that  those  who  did  not  receive  alcohol  were  "  fresher, 
livelier,  and  marched  better  than  those  that  had  alcohol." 
An  experiment  on  typesetters  in  Germany  showed  that  those 
who  drank  daily  three  fourths  of  a  tumbler  of  wine  were  much 
less  efficient  than  abstainers.  Their  work  decreased  on  an 
average  of  9  per  cent.  This  means  not  only  that  the  man 
could  not  do  as  much  work,  but  also  that  his  earning  power 
would  be  less.  On  pages  46  and  323  it  was  shown  how 
alcohol  affected  mountain  climbing  and  marksmanship. 

Decreased  Mental  Activity.  —  Memory  is  a  very  valuable 
quality  of  mind,  and  a  good  memory  is  not  to  be  lost  without 
regret.  Dr.  Smith  showed  in  experiments  that  70  per  cent 
less  work  in  memorizing  figures  was  done  when  using  alcohol 


The  Effect  0}  Alcohol  and  Tobacco 


409 


(Fig.  227).  Professor  Vogt  showed  in  many  experiments 
that  the  taking  of  one  to  three  glasses  of  beer  interfered 
with  the  memory  process ;  that  it  took  on  the  average  18  per 
cent  longer  to  learn  lines  of  poetry.  In  Italy,  where  a  great 


V/////A  Ab 


Effect  of  Alcohol  on  Memorizing 


FIG.  227.  —  Height  of  columns  represents  the  number  of  figures  learned 
each  day.  Increase  from  day  to  day  on  abstinent  days  shows  the  gains 
made  by  practice.  Decrease  of  fifth  and  sixth  days  due  to  temporary  ill- 
ness, and  on  the  sixth  day  one  dose  of  alcohol  was  taken.  Dotted  line  from 
fourth  to  twenty-fifth  days  shows  the  normal  rate  of  increase.  Alcohol 
about  equal  to  that  in  from  two  to  four  glasses  of  beer  (40.80  grms.)  taken 
on  the  alcohol  days.  Memorizing  done  eight  or  ten  hours  after  taking  the 
alcohol.  Amount  of  work  done  on  the  twelfth  alcohol  day  about  70  per 
cent  less  than  it  should  have  been,  and  was  less  even  than  was  done  on  Day 
one. 

deal  of  wine  is  made,  it  was  found  that  the  use  of  alcohol 
in  this  form  even  interfered  with  mental  work  in  school. 
The  following  shows  the  report  on  4000  children : 


462 

ABSTAINERS 

1616 
DRINK  WINE 
OCCASIONALLY 

2021 
DRINK  WINE 
DAILY 

Per  Cent 
42.56 

Per  Cent 
30.5 

Per  Cent 
29.8 

Fair                       

53.49 

41.8 

39.7 

Poor 

3  85 

27 

303 

Now  alcohol  renders  the  user  liable  to  make  mistakes. 
Consequently  the  managers  of  the  Lackawanna  Railroad, 


4io 


Healthful  Living 


after  an  accident  caused  by  the  engineer  going  past  signals, 
made  the  following  rule :  "  Trainmen  must  not  drink  or 
enter  saloons  even  when  off  duty."  This  engineer  had  been 
drinking  and  the  accident  cost  the  death  of  40  people  and 
serious  injury  to  75  more. 

Drink  also  causes  more  accidents  to  the  worker  himself. 
Hence,  employers  are  demanding  that  workers  shall  not  use 
alcohol.  The  following  chart  (Fig.  228)  shows  how  difficult 


Employers  Who  Prefer  Non-Alcoholized  Workmen 

from  f/>e  Report  by  the  US.DFPAffrMFNr  OF  LABOR  of  an  investigation  authorized  by  Conyress,/897. 
\               I     Represents  employers  who  do  consider  en  app/icant's  drink/ny  habits . 
K\\\\\\\\VJ     Represents  employers  who  do  not  consider  an  applicant's  drinking  habits. 
77%  of  A// Establishments  Reporting 

56.5%  of  Mines  and  Quarry-men ^^^^^^ 


72%  of  Agricu/lur/sts 
79%  of  Manufacturers 


88%  of  Trades 

E 

V%  of  Transportation 


FIG.  228.  —  Drinkers  are  not  sought  as  workmen  or  for  responsible 
positions. 

it  is  for  the  drinking  man  to  obtain  employment.  It  is 
harder  for  him  to  hold  it,  if  he  gets  it,  because  he  is  less 
efficient,  more  liable  to  injury,  and  often  causes  trouble 
among  other  employees. 

It  is  significant  that  great  industrial  organizations,  rail- 
roads, and  mercantile  houses  are  requiring  that  their  men  do 
not  drink.  They  know  that  alcohol  in  any  form  lowers  the 
efficiency  of  their  men  and  the  men  are  beginning  to  realize 
that  they  are  more  capable  and  advance  more  rapidly  if  they 
leave  drink  alone.  George  Patullo  writing  in  the  Saturday 
Evening  Post  of  the  encampment  of  the  National  Guard  on 
the  Mexican  Border  says,  "  It  is  growing  to  be  the  same  with 
the  soldier  as  with  every  other  calling.  He  finds  that  booze 


The  Effect  of  Alcohol  and  Tobacco 


411 


does  not  pay,  that  it  is  a  losing  game  and  hurts  his  health. 
He  has  discovered  that  commanders  frown  on  it  and  people 
with  whom  he  would  like  to  associate  are  temperate  and 
prone  to  shy  off  from  a  hard  drinker." 

Insanity.  —  The  sober  man  thinks  first  and  then  acts ; 
the  man  under  the  influence  of  alcohol  acts  first  and  thinks 
afterward.  Alcohol  so  interferes  with  the  working  of  the 
mind  (Figs.  229,  230)  that  the  man  is  unable  to  make  correct 
judgments.  Consequently 
after  a  time  his  mind  is  really 
impaired.  In  the  State  of 
New  York  over  25  per  cent 
of  the  insane  in  the  hospitals 
of  the  state  are  insane  be- 
cause of  the  use  of  alcohol. 
It  is  estimated  that  there  is 
lost  to  the  State  of  New  York 
every  year,  through  insanity, 
over  $2,400,000  and  to  the 
United  States  $12,000,000. 
The  report  of  the  states  in 
which  alcohol  is  not  allowed 
shows  a  decrease  in  the  in- 
sanity of  that  state.  For 
example,  the  State  of  Kansas 
has  made  great  improvement 
in  this  regard. 

Now  at  one  time  it  was  thought  right  and  proper  to  drink, 
and  in  some  places  to-day  drinking  is  a  custom,  a  tradition 
that  is  followed.  There  are  parents  who  drink  alcoholic 
liquors  because  they  formed  the  habit  in  their  youth  when 
drinking  was  considered  less  harmful  than  it  is  known  to  be 
to-day.  The  one  test  of  growth,  in  a  people,  is  to  make  im- 
provements from  one  generation  to  another.  So  the  child  is 
not  to  judge  the  parent  either  as  regards  action  or  motive. 


FIG.  229.  —  This  figure  shows  four 
nerve  cells  from  the  brain  of  a  man 
who  died  of  alcoholic  insanity.  It 
will  be  noticed  that  the  body  of  the 
cells  and  the  nerve  fibers  are  broken 
up  and  degenerated. 

The  changes  shown  in  Fig.  230  are 
the  more  severe  changes,  and  repre- 
sent complete  destruction  of  the 
nerve  tissue. 


412 


Healthful  Living 


The  new  generation,  better  acquainted  with  the  facts,  many 
of  them  discovered  recently,  must  see  that  it  takes  advantage 

of  the  facts  and  does 
not  repeat  the  mis- 
takes of  the  older 
generation.  In  this 
way  civilization,  in 
which  we  all  have  a 
part  to  play,  will 
advance. 

Summary  of  the 
effects  of  alcohol.  — 
In  conclusion  on  this 
question  it  may  be 
stated  that  the  fol- 
lowing represents  the 
results  of  alcoholic 
drinks  as  a  beverage : 

1.  Alcohol     tends 
to    reduce    physical 
strength  and  endur- 
ance and  the  amount 
of  work  done. 

2.  It  impairs  men- 
tal work. 

3.  Alcohol  belongs 
to  the  class  of  habit- 
forming    drugs,   like 
opium  and  morphine, 
which  tend  to  create 
a  craving  for  increas- 
ing amounts.     In  certain  persons  this  leads  inevitably  to 
heavy  drinking  and  its  serious  consequences. 

4.   The  alcohol  user  on  the  average  is  especially  liable  to 
sickness  and  to  premature  death. 


FIG.  230.  —  An  illustration  of  the  nerve 
branches  and  fibers  in  a  case  of  alcoholic  in- 
sanity. The  patient  died  of  this  disease,  and 
when  the  nerve  fibers  were  examined  under  the 
microscope,  they  were  shown  to  be  swollen  and 
broken  down  in  the  manner  illustrated  in  the 
drawing.  The  swellings  of  the  nerve  fibers,  as 
seen  in  this  illustration,  are  characteristic, 
and  are  usually  seen  in  the  brain  of  those 
dying  from  alcoholic  insanity. 


The  Effect  of  Alcohol  and  Tobacco  413 

5.  Drink  increases  liability  to  accident  even  in  the  person 
who  is  never  intoxicated. 

6.  The  use  of  alcohol  by  parents  is  often  responsible  for 
a  high  death  rate  in  children,  or  for  physical  or  mental  defects. 

7.  Alcoholism   does   not   necessarily  mean   drunkenness. 
The  habitual  user  of  alcohol  may  show  some  of  its  effects 
without  ever  reaching  the  stage  of  intoxication. 

8.  Alcohol  is  not  a  stimulant  to  the  nervous  system,  but 
a  depressant.* 

9.  Because  of  the  effect  of  alcohol  on  mind  and  body  it 
is  responsible  directly  and  indirectly  in  the  United  States 
for  at  least  one  fourth  to  one  half  of  all  poverty  and  neglect, 
for  more  than  one  third  of  pauperism,  for  one  fifth  of  the 
insanity  and  divorces,  and  one  half  of  the  crime. 

Tobacco.  —  The  leaf  of  the  tobacco  plant  is  used  for  smok- 
ing and  chewing.  At  one  time  it  was  used  in  powdered 
form  as  snuff.  There  are  many  reasons  why  tobacco  should 
not  be  used  by  man,  and  no  satisfactory  reason  why  it  should 
be  used.  With  this  viewpoint  in  the  foreground  there  are 
some  people  who  say  that  a  person  who  uses  tobacco  is  a 
fool  and  that  he  will  go  insane  if  he  smokes  cigarettes.  Now 
such  a  statement  is  at  variance  with  the  facts.  In  con- 
demning or  praising  any  method  or  practice,  care  should  be 
exercised  in  forming  a  judgment  and  discretion  used  in  stat- 
ing a  belief.  What  does  tobacco  do  to  the  cells  of  the  body  ? 
How  does  it  injure  them  ?  What  may  be  the  loss  in  terms 
of  efficiency?  These  are  questions  that  we  should  be  pre- 
pared to  answer. 

General  effects  of  tobacco.  —  In  the  first  place  we  can  think 
of  men  who  are  strong  physically,  keen  mentally,  and  sound 
morally,  who  at  times  use  tobacco.  If  they  use  it  moderately, 
they  may  reply  to  our  question  by  saying,  "  smoking  does 
not  hurt  me."  By  such  a  statement  one  may  mean  that  no 
perceptible  harm  is  felt.  But,  how  much  keener  mentally, 
how  much  stronger  physically,  would  he  be,  if  he  did  not  smoke. 


414  Healthful  Living 

Smoking  contributes  nothing  to  a  man.  Men  smoke  but 
the  smoking  is  not  a  characteristic  of  manliness.  So,  be- 
cause you  know  men  who  smoke,  do  not  think  that  smoking 
does  not  hurt  them.  Think  rather  of  how  much  better  in 
every  way  they  would  be  if  they  did  not  smoke. 

It  is  true  that  the  use  of  tobacco  forms  a  habit  that  tends 
to  increase  the  amount  of  tobacco  used.  This  is  the  special 
danger  in  cigarette  smoking.  It  leads  frequently  to  the  use 
of  so  many  cigarettes  that  health  and  strength  are  lost. 

That  smoking  causes  undesirable  effect  upon  the  body  is 
shown  in  the  custom  of  college  athletes.  Coachers  and 
trainers  do  not  permit  smoking  by  those  who  play  on  the 
team  and  all  athletes  who  seek  to  excel  in  sport,  do  not  use 
tobacco. 

We  know  that  smoking  impairs  one's  physical  efficiency. 
A  war  correspondent  visiting  the  Italian  trenches  in  the 
Trentino  during  the  recent  war  writes  as  follows  : 

"As  we  pushed  on,  all  our  old  sins  of  pipes  and  cigarettes 
began  to  be  expiated  in  our  middle-aged  hearts.  ...  So 
we  struggled  on,  the  easy  perspiration  bathing  our  bodies. 
Hiatt  was  doing  better  than  I,  being  younger  and  less  guilty 
of  cigarettes.  I  would  force  myself  until  I  could  go  no 
farther ;  would  stop ;  would  droop  over  my  alpen-stock  and 
pant  like  a  netted  fish." 

Men  who  smoke  to  excess  find  that  they  become  nervous, 
lose  their  appetite  for  wholesome  food,  and  show  a  distinct 
loss  in  efficiency. 

The  effects  of  tobacco  upon  youth.  —  The  youth  who  looks 
forward  to  physical  efficiency  as  well  as  mental  efficiency 
as  important  factors  in  doing  a  work  and  achieving  a  place 
in  the  world,  will  leave  tobacco  alone.  The  growing  boy 
suffers  the  most  of  all  from  the  use  of  tobacco.  His  growth 
is  interfered  with,  his  heart  is  injured,  and  his  stomach  dis- 
turbed. If  the  boy  thinks  he  wants  to  smoke,  he  should 
wait  until  he  is  twenty-five  years  old ;  then  with  developed 


The  Effect  of  Alcohol  and  Tobacco  415 

body  and  a  wiser  mind,  if  the  use  of  tobacco  seems  desirable, 
let  him  make  the  choice,  cognizant  of  its  dangers  and  limita- 
tions. The  youth  who  looks  forward  to  excellence  in  athletics, 
to  achievement  in  business  or  the  professions,  to  authority  and 
control  in  store  and  factory,  will  select  his  habits  as  carefully 
as  his  friends,  his  food  as  carefully  as  his  facts,  and  he  will 
leave  tobacco  out  of  the  things  that  are  for  him. 

APPLIED    PHYSIOLOGY 

1.  Should  a  person  with  a  "  cold  "  keep  away  from  other 
people  ? 

2.  What  is  the  value  of  vaccination  ?     Are  you  vaccinated  ? 

3.  Do  you  take  reasonable  care  to  see  that  your  food  is  fresh  ? 
Is  this  important  ?     Can  ill  health  result  from  decayed  food  ? 

4.  What  diseases  may  flies  carry?     How  is  your  home  pro- 
tected against  flies? 

5.  How  many  hours  a  night  do  you  sleep  ?     Does  it  satisfy  the 
requirement  ?     What  is  the  requirement  for  your  age  ? 

6.  Do  you  wash  your  hands  before  eating?     In  what  diseases 
is  this  habit  very  important  ? 

7.  Do  you  sleep  at  night  with  your  windows  open ?     In  winter? 

8.  Do  you  attend  to  the  elimination  of  the  body  waste  every 
day  ?     How  important  a  habit  is  this  ? 

9.  Are  bacteria  destroyed  within  the  body? 

10.  Which  is  the  most  important,  prevention  of  infection,  or 
disinfection  after  infection  has  resulted  from  carelessness  ? 

11.  Is  cleanliness  of  value  in  the  home?     How  much  more 
valuable  is  it  in  the  person  ? 

12.  How  many  Health  Rules  for  Children  do  you  know  and 
follow? 

13.  Is  alcohol  a  food?     How  did  the  Russian  government  solve 
the  question? 

14.  What  is  fatigue?     How  can  you  tell  when  it  is  time  to  rest? 

15.  Are  stimulants  advisable  when  you  are  tired?     What  will 
rest  do  that  stimulants  will  not  do  ?     Is  restoration  of  more  value 
than  stimulation? 

16.  What    is    the    difference    between    natural    and    artificial 
stimulants  ? 

17.  Write  an  essay  on  alcohol  with  reference  to  its  impairment 
of  the  efficiency  of  the  body. 


4i 6  Healthful  Living 

GLOSSARY 

Benzine.  —  A  colorless  and  highly  inflammable  liquid  obtained 

from  crude  oil  by  distillation. 
Depressant.  —  A  substance  that  lowers  the  irritability  of  the  body 

cells,  and  makes  it  difficult  for  them  to  respond. 
Opiate.  —  A  substance  allied  to  opium  and  capable  of  inducing 

sleep. 
Sedative.  —  A  medicine  having  the  power  to  quiet  and  sooth  the 

body. 
Strychnin.  —  A  white  crystalline  poisonous  compound  with  the 

formula  (C2iH22N202).     It  is  a  strong  stimulant  of  the  nervous 

system  and  highly  poisonous. 


APPENDIX 
FIRST   AID    IN    EMERGENCIES 

Artificial  respiration.  —  This  is  a  means  for  getting  air 
into  the  lungs  of  a  person  after  drowning,  smothering,  gas 
poisoning,  and  the  like.  It  is  a  rather  simple  procedure  and 
not  so  complicated  as  a  young  friend  of  the  author  seemed 
to  think  when  she  called  it  "  agricultural  perspiration."  It 
is  performed  in  the  following  way  (Schaefer  Method). 
Place  the  subject  face  downward  on  the  ground,  turn  the 
face  to  one  side,  and  bring  the  hands  to  a  resting  place  beside 
the  face.  Kneel  astride  the  body  of  the  person  and  place 
your  hands  on  each  side  of  the  back  in  the  region  of  the  lower 
ribs.  You  are  now  ready  to  begin.  It  must  be  remembered 
that  the  average  rate  of  respiration  is  about  18  times  a 
minute  and  the  procedure  you  are  to  follow  should  proceed 
at  about  the  same  rate.  (1)  Lean  forward  on  your  hands 
so  that  all  your  weight  may  be  brought  to  bear  on  the  ribs 
of  the  subject.  This  forces  the  air  out  of  the  chest.  (2)  Raise 
your  body  and  release  the  pressure  on  the  ribs.  The  elastic 
chest  wall  will  fill  out  and  take  in  air.  This  pressure  and 
release  at  the  rate  of  18  times  a  minute  will  cause  the  air  to 
pass  in  and  out  of  the  lungs  and  so  will  provide  for  the  neces- 
sary oxygen. 

Inasmuch  as  the  most  frequent  cause  for  the  use  of  artificial 
respiration  comes  from  drowning,  it  is  important  to  know 
and  remember  the  proper  care  regarding  accidents  on  the 
water.  If  the  boat  or  canoe  upsets,  the  first  efforts  should 
be  directed  to  getting  hold  of  the  side  of  the  upturned  ves- 
sel. A  boat  or  canoe  will  float  and  will  support  the  weight 
2E  417 


418  Appendix 

of  several  persons.  After  support  is  obtained,  then  one 
may  look  around  to  see  what  is  the  desirable  thing  to  do. 
In  many  cases  other  people  will  see  you  and  come  to  your 
assistance.  Their  assistance  is  often  too  late  if  the  one 
having  the  accident  has  thrown  himself  around  in  the 
water,  has  called  out,  and  has  taken  a  lot  of  water  into  the 
mouth  causing  choking  and  making  breathing  difficult.  Do 
not  cry  out  as  the  boat  upsets,  for  you  are  liable  to  choke 
with  water  taken  in  with  the  mouth  open. 

Black  eye.  —  A  blow  in  the  face,  by  bruising  the  soft 
tissues  around  the  eye,  may  cause  discoloration.  The  best 
treatment  is  the  immediate  application  of  an  ice  pack 
(chipped  ice  in  an  ice  bag)  or  cold  compresses  applied  every 
half  hour.  If  this  does  not  entirely  prevent  the  discoloration, 
the  part  may  be  painted  by  a  face  paint  but  usually  this  is 
unnecessary.  Beefsteak  serves  no  valuable  purpose  in  this 
injury  when  applied  to  the  part. 

Burns.  —  Burns  are  of  different  degrees  of  severity  de- 
pending upon  extent  of  the  burn  in  area  and  in  depth.  The 
depth  of  the  burn  is  described  as  follows :  The  first  degree 
shows  a  reddening  of  the  cells  of  the  epidermis ;  the  second 
degree  shows  a  separation  of  the  epidermis  from  the  dermis, 
with  the  formation  of  serum  between  the  two  layers  (blister) ; 
the  third  degree  shows  the  destruction  of  the  epidermis  with 
some  burning  and  injury  in  the  dermis. 

After  the  burn,  be  it  from  heat,  chemical,  or  other  source, 
do  not  touch  the  part  burned  with  the  fingers,  do  not  apply 
salve  of  any  kind,  and  do  not  open  any  blisters.  The  best 
first-aid  dressing  is  the  application  of  the  following  on  a 
sterile  gauze  dressing : 

Picric  acid 65  grains 

Alcohol 2.5  ounces 

Distilled  or  sterile  water 1   quart 

This  solution  is  made  by  dissolving  the  picric  acid  in  the 
alcohol  and  then  adding  the  water.  Do  not  remove  the 


Appendix 


419 


dressing  for  three  days  if  the  above  precautions  have  been 
taken.  If,  however,  the  above  dressing  is  not  available,  bak- 
ing soda  may  be  applied  directly  to  the  burn  and  the  wound 
then  covered  with  a  sterile  bandage.  On  about  the  third  day, 
blisters  may  be  opened  with  a  needle  after  its  tip  has  been 
heated  in  a  flame  to  a  red  heat  (a  match  may  be  used  for 
this  purpose).  Burns  which  do  not  blister  are  not  danger- 
ous and  they  may  be  treated  by  applying  sterile  vaseline. 

Broken  bones.  —  A  broken  bone  is  a  fracture  of  the  bone. 
In  case  of  such  acci- 
dent keep  the  patient 
quiet.  If  he  must 
be  moved,  a  splint 
for  the  part  may  be 
made  by  means  of  a 
shingle,  umbrella, 
pillow,  or  folded 
newspaper.  Send  for 
the  doctor.  If  the 
end  of  the  bone  pro- 
jects through  the 
flesh,  do  not  touch 
the  wound  but  cover 
it  with  a  sterile 
bandage. 

Cuts  and  wounds. 
-Keep  the  cut  or 
wound  clean  (Fig. 
231).  This  does  not 
mean  putting  some 
so-called  antiseptic 
on  it  to  clean  it,  but 
it  means  in  most 
cases  putting  nothing  FlQ  231  I  Boy  gcouts  giving  first  aid 

On    it    but    a    Sterile  treatment  to  a  comrade. 


420 


Appendix 


dressing.  If  there  is  dirt  in  the  cut,  painting  the  area 
with  tincture  of  iodin  will  be  good  treatment.  Hydrogen 
peroxide  and  other  first-aid  remedies  are  less  valuable. 
Protect  the  wound  from  anything  that  will  infect  it  as  fingers, 
clothing,  or  other  objects,  and  help  it  to  heal  by  keeping  the 
part  at  rest.  If  the  wound  bleeds  severely  and  the  blood 
does  not  clot,  pressure  (see  hemorrhage)  may  be  applied 
above  the  wound  (Fig.  232). 

If  the  wound  does  not  bleed  freely,  as  in  the  case  of  pin 
pricks,  injuries  from  nails  and  other  sharp  instruments, 

every  effort  at  first  should  be 
directed  toward  causing  free 
bleeding.  Tincture  of  iodin  on 
the  end  of  a  tooth  pick  wrapped 
with  a  small  amount  of  cotton, 
should  then  be  inserted  in  the 
wound.  If  this  treatment  does 
not  effect  a  cure  in  one  day  a 
surgeon  should  be  consulted. 

Fainting.  —  The  practice  of 
throwing  a  bucket  of  cold  water 
on  the  person  who  faints  is  not 
to  be  approved.  If  the  person 
is  reclining,  let  him  lie  and  keep 
the  head  lower  than  the  feet. 
Loosen  all  tight  clothing  and 

gently  fan  the  person  or  bathe  the  brow  with  cold  water. 
Never  give  whisky  to  a  fainting  person.  Keep  people  away, 
allow  plenty  of  air,  and  maintain  quiet.  After  the  attack, 
do  not  move  the  person  for  at  least  half  an  hour. 

Foreign  body  in  the  eye.  —  Cinders  or  dust  particles  in 
the  eye  are  best  removed  with  the  tip  of  a  handkerchief.  If 
the  object  is  on  the  upper  lid,  the  lid  must  first  be  everted. 
This  is  best  done  by  asking  the  person  to  look  down  at 
the  time  you  are  folding  the  lid  back  over  a  pencil. 


FIG.  232.  —  The  method  of 
applying  the  knotted  handker- 
chief to  compress  a  divided 
artery,  a,  6,  track  of  the  inner 
artery  of  the  left  arm. 


Appendix 


421 


In  many  cases  it  is  necessary  to  have  the  services  of  a 
physician. 

Foreign  body  in  the  ear.  —  In  removing  objects  from  the 
ear,  care  must  be  taken  not  to  put  any  instrument  in  the  ear. 
Children  sometimes  put  such  things  as  peas,  grains  of  corn, 
etc.,  in  the  ear.  They  can  be  removed  by  washing  out  with 
an  oil;  do  not  use  water  because  that  will  make  the  grain 
swell.  Insects  should  be  killed  by  oil  and  then  they  can 
easily  be  washed  out. 

Hemorrhage.  —  Hemorrhage  is  bleeding  from  a  part,  but 
this  term  is  not  used  in  the  case  of  simple  cuts.  Where  the 
flow  is  marked,  the  term 
hemorrhage  is  more  aptly 
applied.  In  nose  bleeding 
from  an  injury,  keep  quiet 
and  compress  the  nostrils, 
breathing  through  the  mouth. 
Often  the  nose  bleeds  from 
picking  the  nose  with  the 
finger  nail.  It  is  important 
not  to  pick  the  nose  in  such 
manner,  and  such  bleeding 
usually  comes  from  an  ulcer 
caused  in  this  way.  Such  an 
ulcer  may  need  to  be  cauter- 
ized by  a  physician. 

Bleeding    from   the    lungs 
gives  frothy  blood.     Do  not  be  alarmed  but  keep  the  patient 
absolutely  quiet.     Send  for  the  doctor. 

Bleeding  from  the  stomach  usually  shows  in  vomiting 
and  the  blood  has  a  black  appearance  like  "  coffee  grounds." 
Send  for  the  doctor. 

Bleeding  from  the  bowels  occurs  usually  in  case  of  piles. 
Keep  quiet,  avoid  cathartics,  and  consult  the  doctor. 

Bleeding  from  other  parts  of  the  body  following  an  accident 


FIG.  233.  —  a,  b,  the  track  of  the 
right  femoral  artery ;  the  compress 
applied  near  the  groin. 


422  Appendix 

is  best  controlled  by  applying  with  pressure  a  pad  of  sterile 
gauze  and  holding  it  in  place  with  a  bandage.  If  this  fails, 
pressure  above  the  bleeding  point  may  be  performed  but 
in  most  cases  this  is  unnecessary.  The  application  of  such 
pressure  is  to  be  made  over  the  artery  going  to  the  part  and 
by  means  of  a  handkerchief  loosely  tied  around  the  part 
and  then  twisted  tightly  with  a  stick  (Figs.  232,  233). 

Sprains.  —  The  spraining  of  a  joint  is  due  to  a  twist  or  fall. 
If  the  injury  is  cared  for  at  once  the  best  treatment  is  to 
immerse  the  part  in  ice-cold  water  and  keep  it  there  for  fifteen 
minutes.  If  the  injury  cannot  be  cared  for  at  once,  the  sub- 
sequent treatment  is  the  application  of  heat  in  the  form  of 
hot  water.  In  either  case,  afterwards  the  part  should  be 
strapped  properly  and  the  patient  allowed  to  use  the  part. 
Bad  sprains  should  be  treated  by  a  physician  because  there 
is  often  a  break  in  one  of  the  bones  entering  into  the  forma- 
tion of  the  ankle  joint. 

Poisoning.  —  The  elaborate  tables  of  the  common  poisons 
with  their  symptoms,  antidotes,  and  treatment  are  of  little 
use  because  they  are  too  long  and  difficult  to  memorize  and 
they  are  not  available,  as  a  rule,  when  most  needed.  The 
principle  may  be  taken  as  a  general  rule :  if  the  poison  is 
an  irritant  that  destroys  tissues  such  as  acids,  lyes,  metallic 
poisons,  etc.,  give  to  the  patient  the  raw  whites  of  several 
eggs.  First,  however,  send  for  the  doctor.  If  the  poison 
is  of  another  kind,  a  narcotic,  such  as  chloral,  alcohol,  cocain, 
laudanum,  then  make  the  patient  vomit.  Vomiting  may  be 
caused  by  giving  a  teaspoonful  of  mustard  in  a  glass  of  warm 
water.  This  may  be  supplemented  by  more  warm  water 
and  by  tickling  the  back  part  of  the  throat  with  the  finger. 

In  poisoning,  there  is  always  depression  of  the  vital  powers, 
so  keep  the  patient  quiet,  apply  heat  externally,  and,  if  neces- 
sary, give  artificial  respiration.  External  heat  may  be  pro- 
vided by  blankets,  hot  water  bottles,  or  heated  stones 
applied  to  the  body. 


Appendix 


423 


FIRST-AID    REMEDIES   TO   HAVE    IN   THE   HOME 

Sterile  gauze 

Bandages  of  one  and  one  half  inch 

Alcohol  (grain) 

Tincture  of  iodin 

Adhesive  plaster,  one  inch  wide 

Powdered  boric  acid 

Aromatic  spirits  of  ammonia 

Picric  acid  for  making  the  solution  for  burns 

Sterile  vaseline  in  tubes 

Chlorazene  surgical  cream    .     .     4  ounces 

Castor  oil  4  ounces 

Seidlitz  powders 1  box  of  12 

Mustard,  powdered     ....     2  ounces 

Syrup  of  ginger 2  ounces 

Syrup  of  ipecac 2  ounces 

Talcum  powder 1  tin 

Clinical  thermometer       ...     1 
Red  Cross  first-aid  packets  .     .     3 

Uses  of  these  remedies.     Sterile  gauze.  —  This  is  used  to 
cover  open  wounds.     There  must  be  care  in  handling  so  that 


FIG.  234.  —  Various  forms  of  handkerchief  bandages:  A,  for  the  chest; 
B,  for  the  shoulder,  hand,  and  arms ;  C,  double  bandage  to  prevent  motion 
of  the  arm. 


it  is  not  contaminated.  The  hands  should  touch  only  a  corner 
and  in  no  instance  should  they  touch  the  part  applied  to 
the  wound. 


424  Appendix 

Bandages.  —  They  are  used  to  hold  the  gauze  in  place, 
or  give  support  to  an  injured  part  (Figs.  234-242).  They 
may  be  used  for  sprains  and  with  splints  for  broken  bones. 


FIG.  235.  —  Hand-          FIG.    236.  —  Three-  FIG.    237.  —  Four- 

kerchief  bandage  for  cornered  bandage  for  corner  bandage  for 
perineum  and  hip.  arm.  arm. 

Alcohol.  —  Used  externally  in  sprains,  strains,  and  bruises. 
May  be  used  for  massage  or  rub. 

Tincture  of  iodin.  —  Used  on  wounds  to  kill  the  bacteria. 
May  also  be  used  as  a  counter-irritant  in  sprains  and  strains. 
Adhesive  plaster.  —  Used  to  give  support   to  an  injured 
part. 

Boric  acid.  —  A  saturated  solution  is  valuable  for  cleansing 
and  soothing  the  conjunctiva  of  the  eye.  Used  after  being 

exposed  to  wind  and  dust  or 
in  mild  infections  of  the  eye. 
Aromatic  spirits  of  ammonia. 

FIG.  238. -Four-tailed  bandage.          ~  F°r      fainting,       shock,       Or 

marked  depression,  it  serves 

as  a  stimulant.  One  teaspoonful  in  a  half  glass  of  water  is 
the  dose.  It  may  be  repeated. 

Picric  acid.  —  For  burns.     (See  page  418.) 

Sterile  vaseline.  —  Vaseline  may  be  used  in  all  wounds  so 
that  the  dressing  will  not  adhere.  It  should  be  sterile. 

Chlorazene  surgical  cream.  —  Superior  to  vaseline  because 
of  its  disinfectant  powers,  it  should  be  used  on  infected 
wounds.  It  is  very  valuable. 


Appendix 


425 


Castor  oil.  —  This  is  a  mild  cathartic.  Dose  for  adult, 
1  tablespoonful ;  for  child  6-12  years,  1  to  2  teaspoonfuls ; 
for  infant,  %  to  1  teaspoonful. 

Seidlitz  powder.  — Mild  purge  for  headache,  and  symptoms 
of  constipation  and  sluggishness  of  excretions. 

Mustard  powder.  —  Used  to 
provoke  vomiting  by  giving  a 
teaspoonful  in  a  glass  of  luke- 
warm water.  May  also  be. 
used  in  mixture  with  flour 
(4  parts  mustard  and  7  parts 
flour)  for  a  mustard  plaster 
in  bronchial  and  throat  con- 
ditions. 

Syrup  of  ginger.  —  One  third  teaspoonful  in  a  glass  of 
water  is  used  for  cramps  and  diarrhoea. 

Syrup  of  ipecac.  —  One  teaspoonful  used  with  children 
to  produce  vomiting.  Valuable  in  croup  because  it  increases 


FIG.  239.  —  Many-tailed  bandage. 


FIGS.  240  and  241.  —  Four-tailed  bandage 
for  the  head. 


FIG.  242.  —  Four-tailed 
bandage  for  the  jaw. 


the  secretion  in  trachea  and  lessens  the  obstruction. 

Talcum  powder. — Used  in  sunburn  and  for  drying  and 
soothing  action  on  skin. 

Red  Cross  first-aid  packet.  —  This  outfit  contains  a  gauze 
bandage,  a  triangular  bandage,  and  two  safety  pins.  The 
gauze  and  triangular  bandage  are  arranged  to  permit 


426  Appendix 

application  to  wound  without  danger  of  contamination. 
It  is  very  valuable  for  those  who  are  unfamiliar  with  the 
handling  of  sterile  equipment. 

EQUIPMENT  FOR  AN  EMERGENCY  ROOM  IN  A  PUBLIC 

SCHOOL 
Furniture 

Two  couches  (rattan) 

One  table 

Two  chairs  (wood) 
Closet 

Four  woolen  blankets 

Two  hot-water  bags 

One  ice  bag 

Two  granite  basins 

One  dozen  clean  towels 

Splints  for  broken  bones 
Medicine  case 

Aromatic  spirits  of  ammonia 

Toothache  plasters 

Bi-carbonate  of  soda 

Picric  acid  (65  grains) 

Alcohol  (grain) 

Mustard 

Olive  oil 
Surgical  case 

Sterile  absorbent  cotton 

Sterile  gauze 

Sterile  bandages 

Zinc  oxide  adhesive  plaster 

Sterile  vaseline  in  tubes 

Tincture  of  iodin 

Dressing  forceps 

Surgical  scissors 

Safety  pins 

Book  on  the  treatment  of  emergencies 


INDEX 


Abduction,  92 

Absorption  from  stomach,  166 

Adduction,  92 

Adenoids,  20,  105,  270 

Adrenal,  359 

Air,  composition  of,  268;  foul  and 
fresh,  268 

Albumin,  128, 

Alcohol,  3,  128,  404;  and  the  blood, 
249;  and  gout,  105;  and  insanity, 
411;  and  lead  poisoning,  383;  and 
physical  efficiency,  46,  408;  and 
sunstroke,  382;  as  a  food,  405; 
effect  of,  on  blood  vessels,  232; 
effect  of,  on  nervous  system,  322 

Alimentary  canal,  structure  and 
function  of,  158 

Amoeba,  3,  245 

Animals,  one-celled,  3;  and  primi- 
tive society,  7 

Antagonist,  125 

Antiseptic,  394 

Antitoxin,  375 

Appendicitis,  176 

Appendix,  vermiform,  175 

Appetite,  191,  202,  207 

Artery,  212,  217;   hardening  of,  249 

Astigmatism,  342 

Athlete,  46;  effect  of  alcohol  on,  47 

Athletics,  131,  138 

Auricle,  218 

Autonomic  system,  300;  function  of, 
305 

Axone,  289 

Bacteria,  214,  216,  371;   work  of,  372 

Bathing,  28,  389;   sea,  133 

Blind  spot,  341 

Blood,  amount  of,  in  body,  227; 
coagulation  of,  215;  carbohydrate 
of,  216;  composition  of,  211,  212, 
245;  effect  of  alcohol  on,  249; 
effect  of  exercise  on,  134;  effect 
of  sleep  on,  247;  fat  of,  216;  gases 


of,  214;  germicidal  power  of,  214; 
growth  determiners  of,  216;  pro- 
tective substances  of,  216;  pro- 
teins of,  216;  purification  of,  250; 
salts  of,  216;  table  of  elements  in, 
213;  waste  products  in,  216 

Blood  pressure,  228;  how  to  measure, 
229;  modification  of,  230 

Bone,  broken,  96,  419;  composition 
of,  88;  function  of,  73;  growth  of, 
41,  104;  nourishment  of,  95,  104; 
structure  of  a  long,  87 

Boxing,  134 

Brain,  292,  305;   weight  of,  306 

Breathing,  abdominal,  chest,  and 
natural,  273;  muscular  action  in, 
271;  nose,  270 

Bronchus,  259 

Burns,  418 

Calorie,  151 

Camping,  133,  139 

Capillary,  217,  220,  228 

Carbohydrate,  147,  151,  216,  240 

Carbon  dioxide,  4,  185,  211,  214, 
220,  240,  256-281,  313 

Cartilage,  structure  of,  40 

Cells,  1,  211,  288;  origin  of,  4;  prop- 
erties of,  4 

Cerebellum,  312;  function  of,  312 

Cerebrum,  307;  effect  of  removing, 
308 

Cheese,  197 

Cholera,  372 

Choroid,  340 

Chyme,  167 

Cilia,  260 

Circulation,  aids  of,  235;  action  of 
lungs  on,  238;  course  of,  222; 
effect  of  exercise  on,  237,  247; 
effect  of  massage  on,  238;  hygiene 
of,  245;  importance  of  good,  245; 
lymphatic,  239;  modification  and 
control  of,  230,  248  ;  nature  of,  212 


427 


428 


Index 


Circumduction,  92 

Coagulation  of  blood,  215 

Cold,  taking,  246 

Conductivity,  5 

Constipation,  171,  177;  and  appen- 
dicitis, 177  ;  use  of  foods  in,  177 

Contractility,  5 

Cooker,  fireless,  205 

Coordination  of  muscles,  123,  287, 
298 

Corpuscles,  212,  244;  work  of  red, 
213;  work  of  white,  214 

Dancing,  137 

Dandruff,  24 

Degeneration,  7;   fatty,  128 

Dendrites,  288 

Development,   9,    212;    of    jaw,    17; 

over-,  140;  power  of  self-,  44 
Dermis,  16-23 
Diaphragm,  262 
Diastole,  218 

Diet,  150;  of  different  peoples,  153 
Dietary  of  Atwater,  150;  of  Voit,  150 
Digestion,     and    environment,     191; 

enzymes  and,   155;    of   food,   158; 

and  health,  189 
Diphtheria,  373 
Disease,   3-7,   214,   374;    caused    by 

mosquitoes,  385;    table  of  ways  of 

communicating,  391,   transmission 

of,  393 

Disinfection,  393 
Dislocation,  96 
Drugs,  325 

Ear,  care  of,  349;  foreign  body  in, 
421;  structure  and  function  of,  347 

Eating  and  exercise,  206;  times  for, 
205 

Eggs,  197,  205 

Elasticity  of  the  blood  vessels,  226 

Emulsion,  173,  181 

Energy,  effect  of  stimulants  on,  402; 
expenditure  of,  123,  125;  muscular, 
123;  origin  of  muscular,  42;  po- 
tential and  kinetic,  43;  production 
of,  123,  400-401 

Environment,  369;  and  digestion, 
191 

Enzyme,  155,  173 

Epidermis,  24 


Ergograph,  46,  142 

Esophagus,  165 

Eugenics,  110 

Eustachian  tube,  348 

Evolution  of  the  nervous  system,  65 

Excretion,  15 

Exercise,  3,  127,  172;    an  aid  to  the 

circulation,    237;     corrective,    99; 

effect  on  complexion,  29;   for  foot, 

97;  forms  of,  132;  and  growth,  129; 

and  health,  131  ;  the  heart  in,  230; 

respiratory,  272 
Expiration,  265 
Extension,  91 
Eye,  black,  418;  care  of,  344;  foreign 

body  in,  420;    internal   structures 

of,  339 ;   muscles  of,  335 

Fainting,  420 

Fat,  147,  151,  240 

Fatigue,  46,  321;    meaning  of,  402; 

muscular  activity  and,   127;    sub- 
stances, 127 
Fencing,  134 
Fibrin,  216 
Fibrinogen,  216 
Flexion,  91 
Flour,  199 
Food,  146-157;  composition  of,  148; 

digestion  of,  158;    poisons  in,  378; 

sources   of,    193,    194;     sources   of 

food  elements,  148 
Food    values,    calculation    of,    151; 

table  of,  153 
Foot,  exercises  for,  97;    hygiene  of, 

85;   proper  shoe  for,  87;    structure 

of,  85;   weak,  96 
Fruits,  196 
Function,  6;    of  epithelial  tissue,  13; 

of  skin,  24 ;   of  nerves,  293 

Ganglion,  49,  66,  290 

Germs,  214 

Glands,  14;  lachrymal,  337;  lym- 
phatic, 244;  oil  or  sebaceous,  26; 
salivary,  160;  sweat,  25 

Glucose,  216 

Glycogen,  45,  181,  182 

Grains,  198,  203 

Growth,  4,  211,  216,  358;  of  bone, 
41;  determiners  of,  216,  358; 
effect  of  exercise  on.  129;  effect  of 


Index 


429 


tobacco    on,    414;     and    repair    of 
tissue,  52 

Haemoglobin,  213,  215 

Hair,  30;  care  of,  31;  superfluous,  31 

Health,  4;  cleanliness  and,  279; 
digestion  and,  189 ;  essentials  for, 
139,  251,  280-281,  317-318,  404; 
golden  rules  of,  326 ;  indications 
of,  32 ;  influence  of  exercise  on, 
131,  140,  244;  importance  of  cir- 
culation for,  245  ;  rules,  395 

Hearing,  347 

Heart,  activity  affecting,  230,  231 ; 
as  a  pump,  217  ;  rate  of,  232  ;  rate 
in  animals,  233  ;  rate  in  man,  233  ; 
tobacco,  249 ;  valves  of,  219 ; 
work  of,  291 

Heat  a  form  of  energy,  124 

Height,  129,  130 

Hemorrhage,  248,  421 

Heredity,  110,  129 

Hockey,  136 

Humidity,  269 

Hunger,  353 

Hyperopia,  343 

Immunity,  375 

Impulse,  nerve,  5-8,  45,  50,  51,  232; 
nerve,  in  coordination,  123 

Infection,  211 

Influenza,  389-390 

Injury,  to  blood  vessels,  248 ;  to 
nerves,  294 ;  of  body  by  poisons 
in  food,  378-382;  of  body  by 
physical  agents,  382-383  ;  of  body 
by  chemical  agents,  383-384 

Insanity,  325,411 

Inspiration,  264 

Instincts,  132,  191,  280 

Intestine,  absorption  from  large,  176  ; 
absorption  from  small,  173  ;  large, 
175  ;  small,  169  ;  support  of,  170 

Irritability,  5,  127 

Joints,  89  :  ligaments  of,  90  ;  motion 
in  movable,  90-93 

Juice,  digestive,  14,  156,  172;  gas- 
tric, 166;  intestinal,  173;  pan- 
creatic, 172 ;  salivary,  161 

Larynx,  258 
Legumes,  195 


Lens,  crystalline,  341 

Leucocytes,  213-214 ;  and  bacteria, 
392 

Lever,  115 

Ligament,  39,  90,  96,  98 

Liver,  178;  anatomy  of,  178;  cir- 
culation through,  178;  disturbance 
of,  185  ;  functions  of,  181  ;  micro- 
scopic structure  of,  179 

Lung,  aid  to  the  circulation  by,  238 ; 
external  appearance  of,  261  ;  in- 
ternal appearance  of,  260;  tuber- 
culosis of,  387 

Lung  capacity,  129 

Lymph,  240,  241  ;  cause  of  flow  of, 
243 

Lymphatic,  origin  and  course  of,  242 

Malaria,  385 

Massage,  238 

Meat,  196,  203  ;   extracts,  197 

Mechanism,  neuro-muscular,  122 ; 
table  of  digestive,  184 

Medicine,  patent,  201 

Medulla  oblongata,  232,  312 

Membrane,  mucous  and  serous,  14 

Mesentery,  171 

Metabolism,  5 

Milk,  197 

Molds,  370 

Mosquitoes,  385 

Mucus,  14 

Muscle,  109-121 ;  attachment  of, 
113  ;  cardiac,  112  ;  comparison  of, 
113 ;  coordination  of,  123 ;  kinds 
of,  110;  names  and  positions  of, 
117;  and  nerve,  1 10  ;  property  of, 
109;  involuntary,  112;  volun- 
tary, 111 

Muscular  sense,  352 

Myopia,  343 

Nails,  31  ;  care  of,  32 

Narcotic,  128 

Nerve,  structure  of,  49-50,  289-290 

Nerve  center,  290 

Nerves,  accelerator,  232,  304 ;  ac- 
tion of,  292 ;  cranial,  295 ;  func- 
tion of,  293  ;  inhibitory,  232,  304  ; 
injury  to,  294 ;  terminations  of, 
291 ;  secretory,  15 ;  of  the  skin, 
25  ;  spinal,  295 


430 


Index 


Nervous  system,  arrangement  of, 
295;  effect  of  activity  on,  317; 
effect  of  alcohol  on,  322 ;  effect 
of  fatigue  on,  321  ;  effect  of  sleep 
on,  318;  function  of,  286 

Neuro-iiiuscular  mechanism,  122 

Nourishment,  13,  214,  239 

Nucleus,  3 

Nucleolus,  3 

Nutrition,  hobbies  about,  192 

Nuts,  195 

Organism,  6 

Organs,  6;  of  the  circulatory  system, 
64  ;  of  the  digestive  system,  62-63  ; 
of  the  excretory  system,  66-67 ;  of 
the  muscular  system,  61;  of  the 
nervous  system,  64-65 ;  of  the 
reproductive  system,  67—68 ;  of 
the  respiratory  system,  63,  64, 
257;  of  the  skeletal  system,  61 

Osmosis,  175 

Ovum,  4 

Oxidation,  42-43 

Oxygen,  211,  213,  214,  220,  240,  256- 
281 

Pain,  sense  of,  351 

Pancreas,  172,  359 

Papilla,  16 

Pasteurization,  379  ;  value  of,  381 

Patent  medicine,  201,  251 

Periosteum,  42 

Peristalsis,  165,  166 

Peritoneum,  170,  171 

Perspiration,  15-25 

Pharynx,  163,  258 

Physiology,  3,  12 

Pituitary,  359 

Plasma,  212  ;   work  of,  214 

Plexus,  300 

Pneumonia,  371 

Poisoning,  422 

Posture,  100 

Pressure,  of  the  blood,  228;   sense  of, 

352 
Prevention  of  communicable  diseases, 

388;    of  influenza,  389-390 
Process,  4 

Properties  of  cells,  3-5 
Protein,  147,  151,  240;    of  the  blood, 

251 


Protoplasm,  2,  213,  288 
Psycho-motor,  122 
Pulse,  226 
Pylorus,  165 

Reflex  act,  299 

Reproduction,  5  ;   organs  of,  67,  £« 

Respiration,  264,  282-284;    artificial 

416  ;   hygiene  of,  269 
Retina,  340 
Rheumatism,  162,  239 
Rotation,  93 
Running,  134 

Saliva,  161 

Secretion,  14,  168 

Sensation,  general,  293,  353 

Senses,  classification  of,  232 

Serum,  14 

Shoe,  characteristics  of  good,  97 

Sight,  335 

Skeleton,  use  of,  72  ;   parts  of,  75 

Skin,  dermis  of,   16-23  ;    hygiene  of, 

28;    injury  of,  28;   organs  of,  24; 

protection  of,  26-28 ;  structure  of,  22 
Skull,  75 
Sleep,  318 
Smallpox,  376 
Smell,  334 
Spermatozoon,  4 

Spinal  cord,  function  of,  297  ;   struc- 
ture of,  296 
Spine,  curves  of,  80,  81  ;  function  of, 

79  ;   deformities  of,  97-100 
Spleen,  245 
Sprains,  96,  422 
Stimulant,  128,  154;    artificial,  402; 

natural,  403 
Stimulus,  127 
Stomach,  absorption  from,  168;  as 

a  storehouse,    168;    structure  and 

movements  of,  165,  166 
Sugar,  147 
Sunstroke,  382 
Swimming,  133 
Systole,  218 

Taste  sense,  333 

Teeth,      16-18;      hygiene      of,     20; 

parts  of,  19 
Temperature  of  the  body,  212,  357; 

regulation  of,  357 


Index 


431 


Temperature  sense,  350 

Tendon,  114,  119,  126 

Tennis,  133 

Tetanus,  374 

Theory  of  spontaneous  generation, 
4 

Thirst,  353 

Thoracic  duct,  243 

Thorax,  81 

Thymus,  359 

Thyroid,  359 

Tissues,  2-5 ;  building  good,  52-54 ; 
connective,  38-42;  epithelial,  13; 
kinds  of,  12;  muscular,  42-49; 
nervous,  49-54 ;  how  the  nourish- 
ment reaches  the,  239 

Tobacco,  139,  413-416 ;  effect  of,  on 
the  heart,  249 ;  effect  of,  on  the 
respiratory  organs,  279,  366  ;  and 
diseases  of  the  throat,  163,  366 

Tone,  muscular,  126 

Tonsils,  162 

Touch  sense,  350 

Toxins,  374 

Trachea,  163,  258 

Trachoma,  338 

Tuberculin,  388 

Tuberculosis,  387 

Typhoid,  374 

Uvula,  164 

Vaccination,  376-377  ;   value  of,  378 
Vagus,  232 


Valves,  of  the  heart,  219;  of  the 
veins,  236 

Vasomotor,  center,  232  ;    nerves,  231 

Vegetables,  200,  204 

Vegetarianism,  193 

Vein,  212;  valves  of,  236;  varicos*. 
249 

Ventilation,  275-279 

Ventricle,  218 

Vermiform  appendix,  175 

Vertebra,  77 

Vertebral  column,  76 

Vessels,  effect  of  alcohol  on  blood, 
232;  function  of  the  blood,  225- 
228;  structure  of  the  blood,  223- 
225 

Viceroptosis,  171 

Vigor,  4';  of  the  hair,  30 

Villus,  170 

Voice,  care  and  culture,  366 ;  con- 
trol of,  360-366  ;  effect  of  smoking 
on,  366 

Walking,  104,  131,  134 
Waste  products,  185.  216,  217 
Water,  147,  153,  389 ;  at  meals,  201 ; 
as  a  solvent  for  waste  products,  214 
Weight,  129,  130 
Wounds,  419 
Wrestling,  134  . 

Yeast,  204,  214,  371 
Yellow  fever,  387 
Yellow  spot,  341 


Printed  in  the  United  States  of  America. 


(UNIVERSITY  OF  CALIFORNIA  LIBRARY 
BERKELEY 

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